<human>: Specifics: married for 4 years. Two years in he was caught cheating. I'd had a kid and major unrelated surgery.  He felt it was partly my fault because I wasn't having sex during this time (couldn't... doctors orders)

The most I found out was that he was having sexually explicit chats on yahoo and Facebook. He did this with several different women, some who I did know.  I saw some things I was upset about and due to my vague upset reaction he revealed enough that I knew it was serious and tried to get the details.  He lied many times. I found emails to other guys that he denies. I found out from a girl I knew he'd sent her photos of me. We went to therapy but she wanted him to go on his own as well and he quit.  He said he already knew he shouldn't chat like that.

Flash forward to now. He always has everything erased on his phone. Histories.  Open apps.  He wipes it all clean. So at the end of the night when all he has done is play around on his phone for four hours, I can't see where he was or what he was doing.  I assume he has hidden accounts again and I've suspected he is putting ads on Craigslist but I can't prove anything. He doesn't use the laptop at home. Just his phone. But he is on there all night. 

I do admit to snooping. I try to do it discreetly, but I don't trust him. I think he enjoys this line of sexting, and he doesn't see it as cheating even though I think it is cheating. We have sex 3 or so times a week. About every other day. That shouldn't be the excuse this time. 

So where do I go from here? I'm not snooping efficiently enough to figure anything out, don't know how to do it. If I talk to him, whether or not he is doing something, he will say either way that he isn't. Since I've been lied to plenty, I don't really trust his word. His assurances won't make me feel better.

Could you distill the essence of the text into 1-3 sentences?
<bot>: should I try to catch husband doing something? Give up marriage? Try to live in blissful ignorance and let something go on behind my back?