My characters as spouses

Simon is canonically married. He's a bit of a mess at his canon point, but his spouses married him knowing that. From flashbacks with his first wife, he seems to be a devoted husband. (The divorce was him realizing she didn't see him as an equal, and was also a shit mother. He probably should have done it earlier.)

Bel probably would need pointers in how someone else saw marriage, because the closest he saw growing up was the drow noblewoman-consort relationship, which is inherently unequal. He also probably wouldn't see the need to ask for it, unless it had legal status.

Once he knew what he 'd be doing, he'd be fine (he grasps living with other people, considering their wants and needs, and so on) but it's not something he's used to considering as relationship goals.

While I can see Bel being fine with either polyamory or monogamy, Ilphyl probably needs to be poly and any relationship they are in accepts that they have projects and other things to do. I don't think they'd be comfortable being the sole source of intimacy or romance or anything for osmeone.