im pretty sure being gay is just the way you are, its a trait your born with so no they dont have that luxury of choice.
and for people saying that having a seperate but equal name isnt segregation take this example from my history homework. The Louisiana act stated that "all railway companies were to provide equal but seperate acommodations for white and black races". That sounds alot like what your saying and a hell of a lot like segregation. "seperate but equal" accomodations is segregation/
For most of these sorts of purposes a common-law spouse is treated the same as an actual spouse. So if gay partners can be CL spouses, there should be little difference in that arena.