Why is my boyfriend going cold / distant

For context my F 25 bf M 23 have been together for 8 months. Since we met we’ve seen each other almost every day and have gone on 3 holidays together etc. We get along really well and I love him a lot. I’ve never loved anyone the way I love him. We’ve had our ups and downs and he’s done some toxic things like going through my phone when I was asleep.. I forgave and we over came these as he never found anything. I’ve always been completely honest and loyal and just wanted him to trust me. He’s a great guy and has changed a lot to be a better bf after I brought things up to him that I wasn’t happy out but he struggles with periods where he goes cold and distant on me. I can just feel it when he’s off and when I ask him about it he just says he’s fine. I told him I can’t do this on and off thing as it’s giving me anxiety, one minute he’s warm and loving the next he’s cold and distant. We talked about it and he said that’s who he is and I have to love him as a person with his flaws etc. Then the next day he came over to my house and broke up with me. I was surprised but just said ok if that’s what you want. I then texted him and he told me he was really upset etc and we ended up talking and he came back to my house and said he doesn’t want to break up. I’m just so confused about this whole relationship now- I don’t want to be sitting on egg shells waiting for him to end things. He’s still being cold and distant and I don’t know what to do any more. I love him a lot but I don’t know if he will ever get more consistent or if he will just end things down the line. We have a holiday booked for end of February and another in April but I don’t want him to just stick around because he likes how much I love and care for him.