PISSED

So this morning i heard my boyfriend in the bathroom getting ready for work he left his phone on the bed( he has the password to my phone and no i dont have his) so i tried to go thru his like he does mines and i see a few females inboxing him via facebook sending pics everything saturday my old school had this tailgate we ended up going to his friend sister bday party the same female that call him brother was there well today i had to do a inside look and see that it dont look like a brother and sister bond I've been faithful since i met this man bad part about it we live together was ttc but now idk we had sex yesterday (protection on until it slipped off) now idk what to do cause when he nutted i felt it... i just want a real cool female friend to vent to cause at this point all i can do is cry