Cant help with direct personal experience sorry Aaron as I'm MTF TS.

There are a number of couples on these boards where the male partner has transitioned (MTF) and they have stayed together and the female partners still positively identify as heterosexual (including my wife). So I guess in that respect you may find some help there.

I suspect it may depend on the length of your relationship. I'm female attracted, guys just don't do it for me at all, never have and still don't, but if my wife needed to transition FTM then yes I would stay with him.

So I don't know the answer but what I do know is this. If you truly feel and believe that your are male then irrespective of how much you love your partner you have to tell him. Whether he stays or not HAS to be HIS choice, not yours by you pretending to be female. If you love him truly you will see that is the only fair option. Now HOW you tell him is a completely different kettle of fish Irrespective of what you choose and what happens there will be people here to support you.

Best Wishes