How do the emotional dynamics of same-sex relationships differ from those of straight relationships?

[Skald the Rhymer]

I'm not looking for tales of how the sex is different. But for those of who who have had long-term relationships of both sorts, how would you say the dynamics differ?

[Zuul]

Bisexual genderqueer here, having dated on multiple spots on the gender spectrum.

In my experience, sex matters less than gender roles. When I was younger I didn't recognize that as much and I felt like there was something intrinsically different (and more appealing) about homosexual relationships. But there are homosexual relationships that have a butch and femme and carry out surprisingly traditional gender roles even though neither participant actually identifies as the opposite sex. A butch/butch or femme/femme relationship is quite a bit different from a butch/femme one.

When I was dating a femme-identified woman (and being femme myself), I really, really loved that aspect of things. Just holding her hand and feeling this sameness between us was comforting. It felt right as if something had simply clicked into place. I find the butch look on women extremely visually hot, but the emotional connection doesn't work the same way for me. Likewise, I dated some men who identified with the traditional butch masculine role and it never lasted longer than a few weeks. But I fell madly in love with a somewhat femme man and, again, there was something just terribly comfortable about that similarity, as if this little round peg had finally found its round hole.

I've found little difference, emotionally, between being with a femme woman or a femme man. It feels comfortable and right for me, regardless of what's going on in somebody's pants. Likewise, butch women and butch men are similarly incompatible with me.

[Zuul]

A few more details that came to me as I pondered further: One of the biggest differences between my queer relationships* and heteronormative ones is that in a queer relationship there's no set, cultural pattern for us to follow. You have to talk about things a bit more. It's not tiring or anything, though. It just seems natural to say, "Okay, I'm good doing this, this and this, but I don't like that." There's kind of a negotiating period.

When I dated men who were very much entrenched in this culture's idea of Manhood, it was totally different. I had boobs, therefore I was the female therefore I was a bottom and emotional and liked "romantic" things. There was this set little box to stick me into and to make assumptions about things and having in depth conversations about roles and preferences seemed confusing at best and vaguely insulting (toward them) at worst. Making broad assumptions on someone based on their physical sex seems fine and dandy when they're often true, but IME those assumptions aren't quite so often made between queer people (though I can think of instances where transphobia has led to silly assumptions about gender roles in a queer relationship).

The mileage of others may vary, this is only my own limited experience, etc.

* I'm using queer to refer to anything outside of the standard heteronormative cultural ideas. Femme/femme, butch/butch pairings, same sex, my non-standard gender identity being recognized, etc.