her being lesbian/gay is a very personal thing. you should not end your friendship with her as long as she remains a good friend and does not force her lesbian ways on you.
kya pata jin doosre doston ki khatir tum is lesbian dost ko choro ek din wohi doosre dost tumhare mushkil waqt main kaam na aayein aur yehi lesbian friend aake madad kare.