1000000/10
I am a massive bias. I'm not sorry.
Ok so this ship was more popular surrounding the real people rather than the musical.
Lin, uses his talents not only to grace us with a fabulous musical but to drive us mad with hidden meanings (Alexander would be proud). He uses common theatre techniques to hint romance between the two characters. And I'm not talking about the very obvious, "with a comma after dearest. You've written my dearest, Angelica." No, I'm talking about how he had them sing those lines together as well as "there you are an ocean away do you have to live an ocean away."
In musicals couples will sing at the same time, especially if it's a song declaring their love for one another. Lin uses this technique when Angelica and Alexander sing of how they miss each other, a little too much.
He also ends satisfied with "he will never be satisfied, I will never be satisfied." Revisiting the point that Angelica has given up her chance of physical satisfaction. Pointing out she knows no better than to give everything up if it benefits her sisters.
After the Reynolds Pamphlet was released John Adams did quote "his fornications, his adulteries and his incests." When speaking of him.
The very statement is a dig, not only at his self-admitted affair with Maria but the rumoured affair with his sister-in-law, Angelica. Something that had been protected from public scrutiny due to them both being married, however after admitting to an affair with a woman he barely knew people did question just where Alexander's loyalties lay. Can you blame them really? The man slept with a woman he barely knew. What's stopping him from sleeping with someone he holds closely to his heart? The evidence of an affair, although circumstantial, is persuasive.
The few people that do ship this write fanfic that's either out of character, e.g. Angelica jumping at the chance of an affair. Or way too lovey dovey.
Don't get me wrong it's cute but the pair of them were a lot alike and that would have created a lot of angst within the relationship. Neither of them would back down in an argument and their opinions would probably clash. Also Angelica was good friends with Jefferson, whom was rather flirty with her. So if it had been different Alexander may have been possessive when it came to Angelica being around Jefferson.
A lot of Alexander's biographers say yes, they had an affair. But Ron says no.
Lin and Renee said it themselves, no doubt there was a connection between the two, an emotional affair if you will. They even went as far as to agree that it was intellectual, Renee added "and the next step, I believe would have been sexual" though this has never been proven, an emotional affair is just as damaging as a sexual one if not more so.
To add the cherry on top. Eliza wasn't by his bedside when he died. Despite the line 'they say Angelica and Eliza, were both at his side when he died' in The World Was Wide Enough. Eliza wasn't there. She'd been sent for the moment Alexander had arrived back in New York and she did come to visit him but due to having a toddler to care for, Phillip II, she was not at his side the exact moment he died. Bishop Moore and Angelica were. This was the icing on the cake for people that already speculated the two had had an affair.
My sources:
Alexander Hamilton; A life
-by Williard Sterne Randall.