Always feel like my partner will leave or cheat

does anyone have any tips to help with hyper vigilance in a relationship? In my past relationship I got cheated on and it hurt me mentally, and now with my current partner I always have a constant fear that something bad is going to happen even though I trust him a bunch. Like if he brings up another girl and says oh she said this. And I get so triggered by it, how do I stop. Like I trust him 100% but my mind isn’t letting me, and I feel like I always start this and do this to myself. Or if it’s a girl from his past relationship and something gets brought up about it because of me, and he’s tells me it still makes me mad.

Does anyone else unintentionally self sabotage their relationships? I tend to seek so much reassurance that they get sick of me. I only seek reassurance because I get scared that they're going to leave me (have abandonment issues) and then it becomes a self fulfilling prophecy because I worried so much that it ends up happening. I get trust issues about my partner cheating because I imagine worst case scenarios all the time and it really strains all of my relationships. Anyone else do this? What have you done to help?

For about a month now I’ve been really obsessed with the idea that my girlfriend has feelings for this guy we know if he has feelings for her. We’ve only known him for about a month and we’re not that close to him. The stuff that makes me worried is completely normal for friends to do or are things that aren’t real. . They respond to each other on group chats . They hangout in groups when I’m not there . She finds him funny and smiles when she’s around him . I just have a bad feeling It’s become such a thing in my mind and it’s deteriorating our relationship. Every time I see him and her talk I feel mad and sick and anxious. And now I’m starting to hate him. I feel like I’m being so unfair because she hasn’t actually done anything, and I keep accusing her and treating her like she has. She says she feels like all I see is the worst in her and like she’s a bad person. I’ve brought this up to her many times and every time she tells me she would never cheat on me and that he’s some random guy and that she doesn’t want him she wants me. I just can’t get the idea out of my head, I can’t stop unconsciously looking for signs of romantic feelings between them. I analyse her body language or how she looks at him, I check if there online at the same time to see if their texting or something. It’s really bad. It’s gotten to the point where it’s not about the idea that they have feeings anymore it’s more just I want to get the idea out my head. I want to stop seeing this. Because she would have said something by now. And I know this is coming from a place of fear and insecurity about myself and the way she feels about me, because he’s no different to any of her other friends I just chose him to be the one I worry about. I want to get past this because our relationship needs to move past this and I want to be able to enjoy the time I spend with my friends instead of relating it to this and the idea of hanging out in this group with her where he is, and if causing instant anxiety. She’s not like this, she’s a good person. It’s not necessarily the idea she’ll actually cheat it’s the idea she’ll develop feeling or he will and will make her catch feelings too. It’s all just a “bad feeling” I have and an obsession with this idea. I can’t stand to be around them in a group cuz all I can see is that “she’s in love with him” or “he would make her or does make her happier”