As a straight(by choice) male, I play both male and female PCs with equal enjoyment. The only 'self-inserting' I do is that my FIRST play through will be with a male human. After that, I branch out with other genders and races. But with all of them, I immerse myself in their story. Experience it as they would, not as I would. The characters I create are their own make-believe people, with opinions and beliefs based on my own but very separate from me. They are not me, and I am not them.
That being said, I can't play my male characters gay. They are either 'forever alone', or romance women. That's as far as I feel comfortable taking them. That doesn't mean they can't exist in the game('playersexual', HA!), or that I have any serious issue running into characters who swing that way. I just can't and won't be playing them. Which is sad, since I have had some interesting ideas for gay PCs. For instance*spoilered for space*
As much as I would love to have played such an interesting story, as well as play Dorian's romance in DA:I, I have consistently found that playing gay characters does not work for me, and in fact is a big trigger that sets off feelings I'd rather not deal with when indulging in my Bioware escapism. This is, after all, a video game. Why would I play an optional aspect of the game that I gain no enjoyment out of?
And with my female characters I can play very light on the bisexual side, with a heavy favoritism towards males(maybe 80/20). For instance, *again, spoilered for space*
But a 50/50 bisexual or full-on lesbian is something that I can't play honestly. By honestly, I mean that they would be a fully realized character, not just a fantasy f/f romance where the two characters are simply avatars of my attraction to women. That's not doing justice to the characters Bioware created, and it is cheapening the PC I'm creating. They aren't 'real' for me. I'm not immersed in their story, I'm observing it on the outside. I don't play characters like that. I play them real, or not at all.
Why I am like that with my female characters, I'm really not sure. Probably because at least on some level, I still consider women attractive, even when I'm playing a female PC. But it is male/female relationships that I find more interesting and fun to play and experience. Who the PC is in that relationship is irrelevant for me, since they are both fictional characters that are not me. As long as the relationship is between a man and a woman, I play it.
This is my experience with the romances in gaming. YMMV.