My Cheating Lying Boyfriend 2?

My bf of three months whI consider the love of my life was cheating all this while.. He had another two yr long distance relationship and still went out with me.. I think that he loves me alot but I just cant forget what he did and I am constantly bickering and questioning his every word.. I do love him and the bond we shared is so special but its so difficult for me.. What should I do?? I dont trust him at all..