Trust

Ugh! I usually don't write or even like to talk about this kind of thing with people but... For the sake of my own mental sanity, I'm finally spilling. (Back story info) I was cheated on in my last relationship and currently am trying to deal with my trust issues. A year ago I went camping at a lake with my husbands family. He has a cousin who is of course very beautiful, but I noticed that he started acting differently around me and his family, Especially around her as he would stare at her, taking seconds, third glances, ect. Every time we go to one of his family parties same thing happens and I notice her doing the same. He only watches certain peoples snapchats and of course she's one. That created even more trust issues of course. I understand that guys/girls tend to do this as its natural to notice a physically beautiful person, but it makes me feel like I'm not ever good enough for him especially if he's taking not just one but a couple glances. I've even caught him scrolling on his phone and stopping at girls pictures, then going back and looking again. I have a really hard time with this, even being out in public with him sometimes. The truth is I'm scared. I've already told him straight up I don't trust him as much. He's changed a lot since then especially after letting him know It's hard for me to trust him but it's still really hard for me and I know it's hard on him because sometimes I've assumed and created more hardship on our relationship. I seriously don't know how to deal with it. I'm not jealous, I'm scared. What do you guys think? How can I ease my worry and deal with it?