Need advice

Hi so iv never posted on here before but I’m in a situation. So my boyfriend and I have been together for a hot minute. We found out I was pregnant a couple weeks ago I’m now 2 months. Everything seems to be going perfect but oh was I wrong. So I had this weird feeling he was being sketchy and I know I shouldn’t of but I went through his phone and saw tinder was recently deleted. So me being me I wanted to see if I could get in I know his privacy whatever. I get in and you know what I fucking see him messaging girls for nudes... like I’m in shock literally don’t know what to do. So I asked his what this was all about and all he says to me is “ that wasn’t me”