Need advice

Hey yall. So my boyfriend and I have a 1 y/o & almost 3 y/o. He cheated on me after each baby and made me feel guilty about it because I had been guarded and cold with him throughout my pregnancies and he was always sweet and supportive. I took him back both times. He’s been off and on being able to provide financially and I think struggles with bipolar disorder. Many have said he appears narcissistic. He’s also a high functioning alcoholic. He started a fight a few weeks ago about me not loving him, saying I made him suicidal, and making me feel bad so I assumed he met someone. He’s not wrong, I have been not as open with him but that’s because it takes time to heal after infidelity, and he expects me to just be over it when it keeps happening every year. Went through his phone and yes, he’s been otp and texting a woman and deleting their messages. They don’t seem very flirty but there are some pet names like “love, boo, pookie” & I know they talk about me sometimes so I figured maybe friends but why delete messages? And then I found out he’s been to her place a few times when he said he was out with the guys. I’m honestly over it. I’m tired of being manipulated and just want to pack up my stuff and leave the next time he’s out the house for a while. Should I talk to him first? I’d be moving back with my mom which is okay, we’re currently living with his mom. I’ve been trying so hard to keep this family together and I’ve reached my limit. I have nothing left atp.