How to be sure if you're Bi?

pam
I'm 21 yrs old and had 1 ex boyfriend when I was 15. I have been busy with school and only dated again when I was in college. I'm with a girl now that dresses like a boy and wears her hair like a boy's. She says she's bi but I think she's lesbian. I've been with her for a year now but I still get attracted to boys. I get guy crushes and all and still dream of having a family the natural way. Don't get me wrong. I know I love her. I fell in love with her and at first I tried to deny it. I never felt so loved by a man the way she loves me. When I go out with boys they go straight into touching or feeling you up and trying to kiss me and I feel disrespected and disgusted. When I kiss boys I always match up to those who doesn't know how to kiss. Idk. I may be confused but is it possible to be bi for one person only or to be attracted to guy looking girls only?