At the risk of asking a question that's already been answered, what exactly was Alex and Eliza's marriage like? Considering how she handled everything after he died, I'd have to say that love was definitely there. But you also said that he didn't respect woman, and I'm wondering if that put strain anywhere (you know, besides the affair)
I don’t think it should have to put strain in the relationship to make their relationship unappealing from a fictional standpoint.
He probably loved her as much as he was capable, but as long as he had power over her, there’s an element of control that effects how she would’ve been able to behave with him, and no amount of family connections or wealth truly offsets societal and legal norms. No matter how much he might have deferred to her, he still had the power to overrule her decisions. I don’t think relationships can ever really be fully healthy unless all parties consider themselves equals, and I don’t think that was the case in their marriage.
(Honestly, I don’t personally find any historical relationships between men and women interesting because of this, unless the woman has some major status or physical strength that elevates her, but that’s personal)
Hamilton didn’t respect women any more than the average man of that time- which is not a whole lot. He sexualized women throughout his youth and kept a strong divide between the roles that men should play in the world and those that women should. Which is, again, common for the time. This was during a period when gender roles were becoming more strongly defined, especially among the upper class. He never supported women’s suffrage (which believe it or not was discussed as a serious topic in some circles) or property rights (though Eliza negotiated the purchase of their home herself), and though he helped create grounds for a woman divorcing for adultery in New York, I would doubt that his involvement had to do with concern for gender equality so much as remembering his childhood condition as a result of his mother’s first marriage or wanting to morally condemn other men he saw cheating while he was, at the time, being faithful.
Since there weren’t other liaisons that came forward when the Reynolds scandal went out, it can be argued he was actually more faithful than many men of his status who spent a lot of time in Philadelphia and gathered multiple affairs. It can also be assumed that Elizabeth accepted his flirtatiousness since that was a pretty strong trait of his character and we have no evidence of her complaining about it (of course, what does that actually prove?). She did advise him on political and family matters, but considering her social status prior to their relationship, that makes sense and I don’t think allowing her an active intellectual and social life earns him special praise as a husband.
I’m probably answering your question badly- because I’m just not interested enough to go deeper than this and make a better summary than what you could find from reading Eliza blogs like @runawayforthesummer or on old posts by @publius-esquire or by opening a biography about Hamilton. Their marriage was probably happy in the way marriages were- in ‘love’ with plenty of kids, struggling financially, but with a family and social functions to go to- and in a way that would be absolutely unbearable by today’s standards- with a man who could legally get away with way more than he should, and fully aware of this, could also be rewarded as a great husband just by performing the most basic responsibilities.
My point was, even if a couple is perfectly content with a major imbalance between themselves, it’s not something worth romanticizing. It’s just not.