Search Results: stare at other girls boyfriends

I’ve been going out with my boyfriend for just over 6 months now and we are really in love, I think we are on the exact same page and we can see a future together, we are still young and I’m really not being naive but I really can see a future with him.
I was sitting with his yesterday and because I’m insecure I brought up the fact at how he just see other girls in the street or on Instagram and think wow they’re stunning and then just think I’m awful. He reassured me, like he does all the time, and said that he never looks at other girls like that, he said he doesn’t look at any girl at all. Then he said this “I’m not going to lie to you, when we first started dating I was looking at other girls because of my past, I thought that I was going to be fucked over and messed about so I kept my options open, by the way that never meant I was talking to them because that illogical and wrong but I would stare and look up girls on Instagram, I would never act on it. But now I can’t imagine myself doing that, it’s uust wrong because I love you” that’s what he said, after that I was a bit like, this is bitter sweet, he’s in love with me now but he used to look at other girls in the first month of our relationship, I feel like I was more trusting in the relationship as I never did anything like that. Is his reason justifiable?
It’s really bothering me, any advice?