If you truly are a romantic type, then I think Chromosphere might be able to offer some advice. I don’t see anything wrong with being a romantic per se, but I see it as a form of idealizing, living in a dream world and detaching from reality. That can be good for an artist, but maybe your W feels left out of your dreams? Also, based on what little you’ve told us of your behavior, could you be a little down on the self confidence and maybe a little prone to feeling sorry for yourself (Chrome, jump in here)?
None of that can be good, and for many reasons. I can see how romanticism COULD be a form of escape, and therefore a defense mechanism to shield you from something, possibly intimacy? You convince yourself you are romantic but the detachment with reality precludes you from ever truly being intimate, and therefore romantic. Romanticism might also put your wife on a pedestal, which could be uncomfortable for her. If she has weight problems, could she also have self esteem issues? If so, feeling like she needs to play the role of some sort of princess might feel like a lot of pressure to her, pressure to fulfill your fantasy, not hers. Resentment can grow from that.
Connecting with someone who is grounded in reality, accepts hers as she is, without pretense or expectations might feel very comforting to her. In that way, this other person might fill some of her needs, instead of her feeling like she has to fill your needs (this last bit is just a guess on my part). Anyway, I think there is a lot in your past that you will have to uncover.
BTW, IMO don't waste your time on the other forums.