I feel anxiety when I’m not with boyfriend

I’ve just recently found out that Relationship OCD is a thing. I feel like I relate but it also feels like relationship trauma. I’m in a fairly new relationship and I keep telling myself that things are going great, we are good, he cares for me, but does he? There’s this unbelievable amount of self doubt that sits in me because of what my ex did to me many months ago. I kept getting told that I do too much, i smother, need constant reassurance, then got told that I don’t care enough, the things I do aren’t enough and that I’m not enough. I feel like I am waiting for the day that I get broken up with because of these “problems” just so I can be proven right at the fact that I should be considered unlovable. I go through this every month around my period because I get so emotional and nervous that I stress over the idea that he doesn’t like me. How does someone continue a relationship with Relationship OCD? How do I explain it?

These past few days I was fine. Minimal intrusive thoughts ,no anxiety etc(to add I'm on medication so maybe it's starting to work although it barely is 2 weeks) and today I got a sudden wave of anxiety and it started latching on some thoughts like" what if I'm in denial and I wanna break up with my bf? And what if erp doesn't work for me because I actually wanna break up with my bf?" But they didn't really stay long usually those thoughts would make me spiral for days or so, now they lasted for some hours. And now I'm trying to trigger myself into being anxious again because if I don't it means I don't have ocd and if I don't have ocd it means I don't love my bf and if I don't love my bf it means I have to break up. Idk if it makes sense but the lack of anxiety makes me wonder if I actually have ocd or not.

I'm 18, and been in a relationship with my man for nearly 2 years. I started living with him around 2 months ago, and all I do is think about if he's cheating. We were long distance for a year and a half of our relationship, maybe seeing eachother once every month or two. I decided to move in with him, and ever since all I can think about is if he's cheating or watching porn. When he's in another room I think he's doing something wrong, I have to check on him every ten minutes to ease my anxiety. I didn't have this problem before moving in. Granted he has talked to some girls on his phone, even having his ex on his phone (didn't do anything bad) and he is porn addicted though he is getting better for me. It's gotten so bad I want to leave him. A couple days ago I broke up with him and it absolutely broke my heart, I couldn't bare it so I gave him a month to show me he can do better, and for me to work on myself. If I'm still unhappy with us I'm going to leave. I love this boy more than anything. I'm scared to be without him, this is my first real relationship. At this point I refuse to even sleep until he is sleeping. I don't want to start over, I don't want to leave him, but I really can't take this pain it's causing me. It's all I think about. I've convinced myself so many times that he's cheating, but I know he wouldn't. I question whether it's anxiety or intuition. Maybe I just know deep down he really is cheating and I just don't want to believe it. I don't know. I don't think he would do that, but at the same time he's really into women. I hate that he looks at other girls in a sexual way, it bothers me so much, and we talk about it often, but with it being an addiction it's difficult. He has gotten a lot better since we have talked about it. He understands I have an issue and is usually happy to talk about it over and over and promise me over and over that he's not cheating. He allows me to have his phone whenever I want and everything, I have no reason to think he's cheating, but I can't get over it. It's not fair to him either. How do I deal with this? How do I stop hurting so much?