What do I do?

Hello. So I'm new to this site and I figured I would ask for some advice... my boyfriend and I have been on and off for four years. Mostly together but we have only separated because of porn for the most part, and what porn had sone to our relationship. It was 1.5 years before I had any clue about his porn and I found hundreds of hentai photo sets and gigs and awful stuff saved to his phone. I confronted him about it and he got SO upset... fast forward a few years and it had been a co stant struggle of him lying to me, I feel like I cant trust him with anything he reads or sees on his phone and every time I felt like things were better, I would trust my gut and take a peek on his laptop of phone and there was the same kind stuff....and A LOT of it. This is an issue he has had since he was a kid. I love him so much and the last time we got back together was after our only "real, serious" breakup. 5 months later we came back together and he promised that if we were ever together again I would have full access to his laptop and phone at any point in time. No hesitation.... well a few months go by and I'm pregnant, I have been patient about having access to his phone because I wanted to trust him right off the bat. But one day I trusted my gut and found some porn again. Not alot. and not frequent. But it makes me wonder if he just got better at hiding these things. He is now extremely defensive about the phone and refuses to give it to me. And I am to the point where I want to leave after I have the baby because I'm so tired of being lied to... I know he has been doing better and not watching nearly as much. Only if he is REALLY struggling but I dont know if I can ever get the confidence back that porn stole from me. I dont know what to do.