So lost and don't know what to do need advice

I have been sick since December got hit with rhinovirus covid flu A and then pneumonia just started getting healthy recently. My gut was telling me something was off with my boyfriend. So yes I checked his phone late one night glad I did. He was texting two other woman on FB and his ex texted him on Valentine's Day saying she loved and missed him etc. Now he went by both the girls on fb house and didn't tell me. One is where my major problem is the other one and I spoke and she even stuck up for me when I told her what was going on. Cause I have been married and divorced 3 times all ex husbands are cheaters. So I don't just confront the man anymore she sent me a screenshot of her chewing him out about the other woman and the ex. Anywho the one FB woman I have a problem with when they were talking he mentioned we were in a certain town she asked why and he said giving a "friend" a ride. Mind you me and him were going to my oldest daughters town to have a late bday dinner for me since I was stuck in bed with pneumonia on my bday. And then he got stuck one night ended up mudding and instead of texting me I missed some fun just now and I should of been there he texted it to this woman. Now this woman did text back said he only came to her house to bring her and her mom some tires they can use. And that they were friends from high school which the first woman confirmed they all including the ex went to high school together.

I of course was furious when I read them it was like 2 or 3 am he had to be up for work in 3 hours. He was sleeping so peacefully he did this before on *** before he got rid of it and I had enough so I woke him up showed and read all the proof. I wouldn't have known about his ex but since he has a iphone it wasn't like mine were it disappeared it was in his deleted thread. He of course fought and argued till the wee hours of the morning. He said he was totally in the wrong and that it wasn't what I thought but he should of told me about them and him going to their houses. And that I had every right to be mad and with his ex he said if you read i didn't say I love you or miss you back. I didn't really engage in the conversation but I didn't let him off the hook cause anytime a ex of mine hits me up I tell him and show him and block the ex. I don't play those walking the tight line game and no respect in a relationship. He left for work I sat in bed all day staring outside he came home with flowers and broke down literally crying he thought I'd pack up our kids and he'd come back to a empty home. His ex wife did this to him with his daughter it's one of his biggest fears. Anywho things have been good he gives me his phone whenever I ask or if I ask who he is talking to he shows me. He tells me everywhere he's going and shares his location. But I can't help but get over the anxiety and nerve wrecking it is when he's on his phone around me or a notification pops up. I feel like everytime my heart drops in my stomach it's only been 3 weeks since I found the messages. I'm just devastated I want to try to make this work I always give three chances depending on severity of the issues. He has two strikes he knows if there is a third I'm packing his stuff and putting him out. But I hate that I am a emotional rollercoaster and one minute I'm happy next I'm mad next I'm sad just uggh any advice