Trust issues/insecurity in relationships

Hey fellas I’m wondering how I get over paranoia and trust issues in a relationship. I try to filter out the thoughts as white noise, but I had this problem in my last relationship and don’t wanna repeat the same mistakes in my current one. It’s like every time I don’t know what they’re doing my mind jumps to “they’re cheating,” which I know isn’t rational and at least this time I have the awareness to recognize that.

3 possible reasons I came up with are: -I’m insecure about myself and think I’m not enough for someone. Like every time I would see my partner going out and doing something cool I would feel inadequate -I’m projecting subconscious feelings that I want to cheat myself, and assume that my partner would want to do the same -spend way too much time online and makes me feel like cheating is such a common practice that happens in every relationship

I’m not sure which explanation would fit best but if anyone has tips I’d appreciate it