We have your standard 50s couple as *gasp* a plot device so that you can have a child. Which obviously be part of the main quest. Thats it.
For all we know it was artificial insemination for some vault experiment. You can still be gay, congrats.
So what exactly is forced upon your character?
1 child and a marriage (could be explained away through so many different means)
Other than that... Yeah. Its still open ended.
OUTSIDE of that, why does your characters sixual orientation matter? For your roleplay? Great. You can still do that.
Its the wasteland, there will be prosttutes, and they won't care if you have the caps. Previous fallout titles have shown this.
Companions will probably be a mixed bag of everything