Touching himself

So I've been with my boyfriend for about a year now and when we started having sex he would touch himself, jack off in front of me and at that time I was fine with it n found it kind of hot but now the sex has gotten way better and it kind of bothers me like we'll be making out getting into it n he'll randomly start doing it and then go back to the sex and then stroke himself a little bit and get back to it and so on. I feel like maybe I'm not doing such a great job? Like he HAS to do that to stay in the mood? Or maybe he does it cause I encouraged it from the beginning? Ugh idk what to do! Help?