Struggling to trust my boyfriend

I (23f) struggle to trust my boyfriend (28m)

I don't find other men attractive. The moment I start being interested in other men, it's sign to me I'm losing feelings for my boyfriend. I see and feel them as much as I see paintings and say "it looks nice".

Now, I've been in 2 relationships before this and got cheated on multiple times. It was really messed up to put it short.

Which is why my rule in dating is no guys that watch porn or flirt/look at other girls.

When I met my boyfriend, he brought up on his own that he thinks there is no room for porn in a healthy relationship and that he is same as me when it comes to relationships, as we talked about religion and values.

Well, internet is full of guys talking about cheating and lying to their gfs about porn and other girls - which is why I'm trying to use it as little as I can.

Should I believe my boyfriend he is being honest about it? Is it possible for other people to feel the same as me?

Yes, I am in therapy for it.

Tldr; I had a lot of awful experiences with guys which makes me struggle trusting current boyfriend. Should I believe he is honest? ------ edit: I never told him he cant do these things and i dont know which part of my post said i told him not to. I wrote specifically he said it himself before we got in relationship when talking about religion.