I am with her for 3 years already and she thinks we will get
married. But after this relationship with her I found out that I’m
gay and I’m very sure now. She is a stunning beauty but I can’t
seem to get on bed with her each time she suggests we do it I tried
but I have little feeling compared to when I fantasize about guys.
I still love my gf but I feel it’s not fair to lead her on since I
am sure of my sexual orientation now. How should I tell her
this?
Certainly, it must have been a shocking to any
partner on the receiving end for such devastating news. For a gay
person to engage in a heterosexual relationship is actually quite
common as the revelation will sink in after they realized that they
are not sexually attracted to their partner, which will spark a
reflective, introspection journey that end up with your kind of
conclusion.
I think your relationship with her will eventually deplete its
meaning because this new found knowledge about yourself will make
this equation an error, serving nobody's needs.
Telling her honestly will likely to be met with denial and
bitterness. You must anticipate that pain is inevitable - it
depends on how swift the cut you want to deliver, instead of
dragging this doom relationship further into some illusion of
grandeur. 
Cheers
