I need help

I have been dating my finace for almost five months now we got pregnant in December and misscarried shortly after finding out  we were pregnant . A few days ago I went threw his Facebook messages and saw that he was sextexting another man    Just two days after   We got together he's (bisexual) I have known my boyfriend for four years and this  is the hardest thing ever  I don't trust him  anymore the first  problem was finding nudes from other girls  and now this I don't know if I can get past it I just moved in with him  about two weeks ago and honestly my heart is broken  can't believe I found  what I found advice please