Relationship anxiety

My last relationship I was in for two years. I was very much in love and I believed he was too, as he got me a promise ring. Things started getting VERY bad emotionally and he treated me very, very poorly. He then cheated on me, on my birthday, with an old friend of mine.

Leading up to this, I had felt anxiety that he was cheating. It turned out to be true.

In my current relationship, it is the healthiest and happiest one I have ever been in. My boyfriend treats me how every person has hoped to be treated, and I am very lucky. But I cannot shake this anxiety that he is cheating or doesn’t love me as much. It is only a physical feeling because I see his actions and I hear his words - there is no doubt in the world that he adores me and that I have every reason to trust him. But I am terrified regardless because I love him worlds more than the first boy, and I can’t stop thinking that he could be the one. This anxiety needs to end. Can anyone share their experience or advice?

(p.s. - yes i have expressed these fears with him and he responded with so much reassurance and love. He always encourages me to go to him about this stuff, but I do not want to continue to share anymore because I do not want him to feel as though he is a problem. This is personal and requires work and healing for myself.)