Transgender and scared to enter a relationship.

I was born female... but I have always felt like a boy, even at a really young age. I look male, though obviously smaller. I have no breasts (had them removed) but I still have female genitalia. I'm happy with my image now, my breasts were always my biggest issue and at least now I can look in the mirror and see the boy I feel I should be. But I'm still attracted to males and I'm finding it hard to find someone I can share my life with... I'm 22 now and have been single since 18. I tend to attract men expecting a man, but they get cared off when I tell them I'm biologically a woman. I have no idea what to do or how to approach this situation... If I guy comes to me, starts hitting on me, then want to see me again... what do I say? "Sorry, I have a vag" doesn't seem like a good line... I'm so lost, I feel like I'm always going to be alone...