Husband on grindr

6 months ago I found grindr app in my husbands app history. First he said he never downloaded it then he confessed - 15+ years ago (we're together 8, married 3) he woke at a house party to a man giving him a BJ, this turned to sex. He never said stop he went along with it. This is the only male/male encounter he's had (apparently) He's downloaded grindr multiple times through out our relationship when extremely drunk, he said he never met with anyone, he would just scroll, then delete the app. The next day he would feel sick for looking on the app. He looked on it out of loneliness - his words (he doesnt have close friends) He's watched and masterbated to gay porn but the thoughts of having sex with a man is not something he wants, he doesnt find men attractive, doesnt consider himself bisexual either.

Its not the fact that he's had sex with a man, that part doesnt bother me. What im still struggling with is being on the app throughout our relationship, in my eyes its cheating. Ill never know what went on because he's lied to me. 6 months on, its all I think about, can the trust ever come back. Would you stay or leave ? Hard when there are kids involved. Thanks guys