I admit to slight metagaming in this area. Note that I have not engaged in this sort of RP in EVE, though I have in other games like SWG, so my comments about my own experiences should be seen in that light. Casiella actually has hacked her implant to, erm, take care of her needs from time to time and shuns any sort of relationship. I might someday explore this with an alt, however.
First, I have never RPed an IC same-sex relationship. I'm just not comfortable with that for myself, though I've had IG friends in all sorts of RP configurations and I even frequently do not know (nor care) about the other player's RL gender or orientation. Despite Evanda once assuming that, being a G.I.R.L., I was almost certainly playing a lesbian, that's not so.
Second, after some bad experiences, I generally do not like any sort of relationship RP without a good bit of OOC communication before. I need to make sure that everyone involved knows "RP != RL" and "IC != OOC". In other words, my character might hit on your character, and might even go further, but that doesn't mean we have any sort of relationship. I'm a happily married man with kids who intends to stay that way. Preferably, the other player is also happy in a RL committed relationship and won't misconstrue anything. The two IC relationships that felt the most "real" for me both occurred with individuals whom I knew to be in marriages, and in one case I even chatted from time to time with one of their spouses.
Finally, if the other player annoys me OOCly, there'll be no IC relationship. This doesn't contradict the previous point. It works with it. If we can't get along, then there's no point in trying to have any sort of fun together.