Insecure

So, lately I've been feeling really insecure. My boyfriend and I have been together nearly 2 years and as time goes on I can feel myself getting really territorial and insecure when it comes to other women. It's not anything that he is doing that's making me think he could cheat or disrespect our relationship. It's just me.. I'm not sure what to do about it or how to explain it better. I just want to go back to being confident again... any tips?