Hi , I (21 F) have been dating my (22 M) for 3 months and me and him both have had shitty relationships and have been cheated on but I can’t shake this “too good to be true feeling”

He got out of his previous relationship with (36 F) a month prior to us getting together and they have a kid together (6 months old) now he hasn’t done anything that would point me too feel this way. I’ve heard his family talk about how horrible she was to him, how he shouldn’t of stayed with her that long if he lost feelings, and his friends have said the same sort of thing but more explanatory. He’s also open and honest, dosnt hide anything and will calmly explain things to me / reasure me any time I need since I’ve very upfront about my mental health and past traumas.  

Him and I have had long conversations about our future, what he wants in a wife and what I want in a husband and over all just our end goals for our life’s and we’ve talked about spending the rest of our life together. 

Now usually when I get anxious like this I try and think logically, like when his Ex tried telling me he cheated on me I thought logically and figured out it couldn’t of happend based on facts. Now usually that works but it always comes back and tends to sneak up on me. 

What are other coping mechanisms i could I try? What has worked for y’all? Any advice on how to shake this? I really do love him and see our future in his eyes and I don’t want to self sabotage.