Fear in my relationship

I have been with my partner for nearly two years. We live together and love the life we have. He’s kind, funny, understanding, affectionate and loyal- everything I could ever want. But I am so anxious of cheating or lying because of exes in the past and I’m worried it’s going to drive us apart. When I get thoughts like “is he cheating on me” “who’s he texting” and “he doesn’t love me just telling me what I want to hear” I try not to react because I know it’s my anxiety, and we both talk about it a lot and he understands it’s anxious thoughts rather than my true feelings. I just wish I didn’t have those thoughts in the first place. Its tiring and brings me down. Even seeing my friends in happy relationships can trigger me because it makes me analyse our relationship. I’m constantly worried about the spark going and us not being as in love as when we first met, even though we have both said we feel more in love than ever. I wish I could believe him and trust him because he’s done everything right. How do I get rid of these thoughts and feel free in my relationship?