recent breakup

so my ex and i dated for almost 7 months started back in september. we had been friends before that since march and we weren't fully a normal friendship and i was ready to date him by the summer but he never wanted to because he thinks he's a bad person and doesn't deserve to have anything good for himself. he's always had issues in his past with relationships too, after a while of dating he just doesn't think the relationship should continue for the other person to succeed in life i guess, it's hard for him to explain why he feels like this. it wasn't any different with me but he also wasn't thoughtful didn't go out of his way to make me feel special with little things . The only times he ever did was if i was upset with him and that was like twice that he did that it wasn't every time. He wouldn't plan special dates for us to go out on at least like every 2 or 3 weeks, we only went on like 2 special dates. Most times we'd hang at my place or go out to eat, nothing more. I wanted more and i thought he could do more but i gave him so many chances. He didn't get me anything for valentine's day (i did and he knew 2 weeks in advance) or for my birthday. I spoiled him and i wanted to be spoiled back. I'm glad we're not together but we're in the same friend group and like even the prospect of him possibly seeing another girl in that group makes my body burn. I know he isn't gonna date for a long time bc if his issues but how do i get over getting jealous.