Agrippa further speak.
In the case where Antony wishes to kill Cleopatra, I believe it is another act of a topic that was discussed earlier: passion. I don't think he would have actually done it, as he is too pussy-whipped and wouldn't want to completely abandon all chances of winning against Caesar.
When it comes to political loyalty in this play, I believe that those who serve their leaders do so because of how they know them. Caesars men all have great respect for Caesar, and Antony's act likewise. The loyalty to each man is based off of their past deeds, and some go far as to kill themselves than see they leaders dead or totally disgraced (as evidenced by the guy who killed himself instead of Antony. Don't judge me I forgot his name).
In Enobarbus's case, I think it was his rational reaction to an irrational man that led him to desert. Though he loved Antony and believed in him, he knew the path he was on was self-destructive. I think that's why he ultimately deserted and betrayed him. As we know, it caused him so much emotional anguish that he died. What a loser. As to who's at fault in this situation, I can't really say. Obviously Enobarbus didn't need to betray him, but he was driven to do so by Antony. I think it's both of their faults.
When we talk about Antony's loyalty, we're talking about two things: where it is, and where it should be. Obviously it is with Cleopatra (though I personally think it should be with Rome). Though his words above might indicate otherwise, he's been loyal to Cleopatra throughout the play. His passions wish for her death, but he ultimately crawls back to her (literally and figuratively). I think he believes his duty to Rome is be ruling it. I really didn't get any kind of sense that he was loyal to anyone but Cleopatra and his own cause. If he had defeated his enemies and been victorious, I'm sure he would've been able to remain loyal to Rome, Cleopatra, and himself (but the capital of the Empire would've moved to Egypt so Cleo wouldn't bitch so much).
Love:
I think this story isn't about love, but about the dangers of what can be perceived as love. I really think both of these bozos were thinking with their proverbial dicks throughout the entirety of the play. They were too worried about who was more powerful or who had influence over the other or whether or not the other one was staying loyal. I think they passionate and irrational behavior in the name of "love" is what this play is really about. The real tragedy here is how both of the title characters abandoned themselves in hopes to please and control the other. If love means killing yourself because you think your "significant other" committed suicide even after they royally fucked you over multiple times, I'd rather pass. For me, the power of the play comes from the loss of power by the title characters. They were so caught up with their "romance" that they let go of all of their power. Maybe I just don't get love, or maybe I have a different view of what love should be. But whatever the case, if Julia had pulled half the shit that Cleo did with Antony (in a proverbial sense obviously, because neither of us are ancient world leaders), I sure as shit wouldn't go back.
If you ask me, Antony and Cleo's love for each other was definitely due mostly to Cleo. She knew that, to maintain her empire, she would need to woo over one of the Triumvirate (which is why she had kids with Caesar Sr. and Antony). She wanted to keep him because he played an integral role with the relations between Rome and Egypt. When looking at it this way, I think their relationship was a shame from the get-go. However, if you ignore this whole bit, then you can really tinker with some interesting concepts. Namely, why was Antony in Egypt in the first place? I don't remember, so I'm just gonna explore a few reasons why:
1. HE WANTED SOME POON:
If he was just there to get laid and chillax, then he's an idiot. Obviously if this were the case, then his relationship with Cleo would be fucked from the start. There's no way in hell he should expect to be one of the three most powerful men in the world, and not get shit for just chillin' out in Egypt. His responsibility is to RUN ROME. Making peace with other kingdoms. Taking over the known world. All that jazz that normal empirical leaders do. If he was there just to get poon and chill out, then yeah. The relationship was fucked from the start. In this scenario, their "love" was the reason for their downfall.
2. HE WAS THERE FOR POLITICAL REASONS
If he was there to ensure Egypts cooperation with the Romans, then I guess his relationship with Cleo is aight. Obviously it's not ideal, because if he was truly in love with Cleo, then his loyalty could come into question (as it should if this were to be the case). However, if he loved Cleo and remained constantly and totally loyal to Rome, then don't think their relationship should have been doomed from the start. In this scenario, it would have been political reasons that ultimately ruined their "relationship."
For all of the servants, their love is out of both duty and love. Obviously Enobarbus, Chairman, and Iras all have long histories with those that they serve, and the thought of living without them must have seemed unbearable.
The whole part where he decides to marry Octavia and completely disregards Fulvia is strange to me, as it makes it really seem like everything he does is politically motivated. However, when regarding his passions for Cleopatra, it just further convinces me how pussy-whipped he is that he would abandon thoughts of his dead wife to convince Cleo of his "love." Obviously he didn't really love Octavia, as he just went back to Egypt to keep screwing Cleo after they got married, so I'm convinced that marriage was just a political move (and a dumb one since he wasn't going to keep it).
Anyway, I think all the characters have a fucked-up way to show love.
Power:
If you think love and politics can mix, then you've obviously never seen House of Cards. In the show, Frank Underwood doesn't actually love his wife, Claire Underwood. He constantly uses her as a political chip. He uses her mothers illness to buy him time. He uses her as a campaign tool to win voters over. He uses her a surrogate and messenger, because she's been with him from the beginning. This, in a lot of ways, is like Antony and Cleopatra's relationship. But Antony is Claire, and Cleo is Frank. And here's the real kicker: neither of them love each other, but they love having the power. And their compatibility and capability for gaining power is how they manage to stick together. It is a (often tense) symbiotic relationship.
I imagine Antony and Cleo's relationship much like this, but Antony is too pussy-whipped to care. He thinks he's in control, even though Cleo obviously has him drooling at her feet. She just wants to stay alive man! You can't blame a girl for that. As for Antony's blame on Cleo, he should take a step back. He's the one that fucked himself over FOR Cleo! If he wasn't such a horny teenager, he probably would've realized she was manipulating him and controlling him. As for letting politics and love mingle, I honestly can't say. I still don't consider what Cleo and Antony had "love," but who am I to judge?
You honestly think Antony takes his role in the Triumvirate seriously?????? After the shit he pulls???? If he really cared, I don't think he would have allowed himself to become spoiled in Egypt, letting his honor amongst influential romans falter. The other two thirds of the triumvirate were perfectly happy with staying in Rome to run the place. Antony thinks that he'll be fine to just hang in Egypt and not participate in running (what was effectively) the most powerful country in the world. I think Antony's downfall isn't the fact that he lost his power in Rome, it's the fact that he didn't bother trying to keep it.
Obviously the play is about political power. It's about how political power gets fucked over by "love." Again, I don't think the tragedy here is about any kind of lost love, I think it's about the loss of power over "love."
Aight fam, listen. I just belted out all this crap above, and I am not about to research 17th century English politics to answer this one. But I'm sure that Elizabeth did just that. She wanted to keep the power within her (albeit probably) extended family.
Transformation:
Going back to what I said about "love" and passion, I definitely think many of the choices made passionately made. Just consider how many times Antony wanted to kill Cleo for betraying him, only to commit suicide after he thinks she's dead. That's just dumb thinking. Like seriously. He's an idiot. I don't think Cleo changes at all in regards to her love for Antony, which is a huge rip on Antony. She only kills herself after she realizes she's totally boned.
Enobarbus is the only rational character in the play. He tries to help Antony make the best choices, arguing against the war at sea. He eventually realizes his friend Antony is gonna screw himself out of any kind of future due to his rash decision making. I think he adds this sense of sadness to Antony's fall from grace. Enobarbus is transformed by the conditions that surround him, rather than he being transformed himself. This transformation is important because it is very different from Antony's, but still unlike Cleopatra's, even though her transformation is also due to her circumstances (though she has a much more... involved role in them).
I don't think any of Antony's transformations can be trusted. Every time he ends up going back to Cleopatra, slobbering, apologetic, and forgiving of her misdeeds. I think the only real transformation that Antony goes through is his abandonment of his duty to Rome. When he decides to go back to Egypt and cheat on Octavia.
Guilt and Blame:
Cleo's lack of regret all ties back to her real motive for "loving" him: it was a political move to try and ensure her power in the region. After she realizes that Antony might kill himself if he thinks her dead, she only sends the messenger to him because she realized his death would mean the end of her.
I honestly don't know if Antony regrets his actions. To me, it doesn't matter. He screwed himself over so many times in so many ways that it really makes no difference if he regrets it. I'm sure he does, though. After all, he was one of the most powerful men in the world at one point, able to leave a legacy to last generations.
I don't think, when you fuck up as bad as Antony and Cleopatra did, regretting it will make it all better. They closed some doors that couldn't be reopened, and they paid they price for making shitty decisions. There's a reason they call it a tragedy.
Enobarbus' death and betrayal are, again, a sane person in an insane position. He was overwhelmed by the impossible position he was put in. And though he loved Antony and respected him, he knew his actions were destroying his legacy.