So to this, honestly the only person who feasibly works in a relationship with aymeric and ennius would be estinien .

Hilda and Leofard have both expressed genuine feelings for him at one point and he shut down Hilda and Leofard for the same reason in canon.

In an au where he wasn't with aymeric at all, or at least cut it off at stormblood, hilda and leofard would be in a relationship with him where they're all okay with it each other so it's mutual on all sides.

A lot of ennius' self doubt for himself stems from stormblood where his mindset of he's not a good person comes from his feelings during that time. He didn't think badly about himself in hvsw because in his mind there was nothing to be sorry about, he was helping people who couldn't be helped even if it was done in a way that wasn't considered morally good.

Stormblood however has him with these mixed messed up emotions about war and the way the political leaders deal with it. With how zenos makes him feel every time they spar and he ultimately gets violated and he okay with that. (The trauma guilt, lots of overdue emotions from his youth there) and how he understands how he essentially trained aymeric to be his and dealing with the repercussions that he made something twisted and ugly inside aymeric .

I've mentioned before that Aymeric isn't really jealous post marriage. He's pretty secure in that regard because he does understand that him and ennius are not... normal. But pre marriage aymeric let a lot of his jealously show/_\