Struggling!

So my boyfriend of nearly 4 years cheated on me about six months ago it got bad I ended up getting a op against him because he was getting very aggressive the closer I got to full on proof of him cheating. He left state for the two weeks of the op, then contacted me after it was up asking if I would give us a second chance, he said he knew he made a huge mistake, he has taken all the blame for cheating. He started going to counseling is even willing to do couple's counseling. But what I am struggling with is I still feel like he is lying to me and hiding watching porn and possibly more from me, but of course any time I say something he says he isn't doing it. But notification in his email says thanks for signing up for the site, and most recently notification of this app for his phone has been showing he is using . A app from thinkyeah that hides everything from websites to messages and phone calls, Facebook accounts. It literally advertises for chaters to hide what they are doing. But again I confronted him and he swears he doesn't have that app.bit with out taking g his phone and checking which he says I can but also if I do he feels it will make him lose trust in me...I don't know what to do.. on the front he is doing everything he should be to make me believe he wants us to work, but I can't shake that he is hiding and lying to me still and I am just scared of being blindsided again.