But you're not really changing their sexual preferences - theyre obviously attracted to you as you are, or they wouldnt be with you.
That only works if the person was okay with being a transexual.
so it's not about their sexual preferences changing - it's about them not being comfortable with their sexual preferences (imo)... which is their problem really.
People should be allowed to be straight though. No problems with people who like trannies, but if you don't find them attracted then I don't see why they need to me. I know you are not explicity saying that, but I do see more and more people being grilled simply because they're not attracted to the same sex and such.
ie I could say I wouldn't be comfortable being with someone whose past life was x, y or z, but they're not legally required to inform me of everything in their past.
If my partner was originally male, she should tell me since as you said yourself: couples need to be honest with each other. Personally I'd accept that and move on, but some people won't. I don't see it as insecurity unless the person reacted really badly to it.
Also people who are infertile can choose to hide that from potential partners too
I also find that deceptive. Same with STDs, I'd rather would know if my partner had something that could harm me.
So I agree you should tell your gf/bf. But it's not really a transsexual issue, more an issue of honesty/trust itself
My point was more honesty/trust too.