Relationship advice

Me and my boyfriend have been together for 6months and everything was going well. He was really into me and really wanted to be with me. I had troubles with my ex who left me on and off for a year, so he could go out and drink etc. So now I’m always worried people don’t want to be with me and will leave me constantly, and I always ask my boyfriend if he’s going to leave. I understand it’s annoying for him but I’m scared of him doing the same as my ex and not wanting me etc. He’s become really different, he doesn’t want to cuddle anymore, he is easily annoyed by me, he doesn’t pay much attention to me when we’re together and I tend to end up talking to myself, I’ve sat and cried in front of him, and he said ‘what’s wrong’ and then ignored it. He can be quite aggressive in arguments and I just don’t know what to do, I know it’s probably my fault. Any help?