Is it normal if i want to let him go to pursue another girl?

I could be insecure but whatever. I have a good eye and know what's going on. Usually end up right which could suck sometimes like this. I know the guy I'm unofficially with right now has something for this other girl. He's always had even when we weren't that serious I could tell. In fact it wouldn't bother me back then because we weren't that close but now, yeah its a problem. Although we are free to pursue other people, that doesn't apply for me. If were "getting to know each other" because we see a future but can't be fully together at the moment, then were not allowed to see other people. As much as he has tried and let me know he just wants me, he's a guy and he will try to lowkey pursue someone else. I've seen the evidence and just cause im still with him, doesn't imply that I'm blind. He prob thinks that but if I let him go and tell him so he can be free to be with her or anyone else, hell prob feel a sense of relief but wnt be surprised if he comes running back to me cause he realized how much I was there for him. However, I have this horrible feeling that they are a better match than me and him. Rather than letting him suffer and thinking of pursuing her, I'll just let him go and actually do it. I wnt be surprised if they make it to a good point. To he honest, I rathernlose him to someone I think is better for him than to just another girl who I kno isn't better than me for him. Yeah at the end kd the day, I'm the one who ended up w him and she could just be eye candy or his fantasy, but hell never know until he tries and see for himself then well all know whats best. I'm crazy about him but I guess my insecurity is getting to me w this one.