Let me paint 2 scenarios for you. Your boyfriend has an ex who he was with for a long time and he tells you about it.

1) Oh we were great friends and I was so in love with her but she ended it and I still love her.

2) It didn't end very well. We fought a lot and she was horrible to me and I really didn't love her at the end.

Which is the way you would want it to have ended?

I'm not saying that your bf is lying to you but he may be trying to spare you some anxiety if he knows that you have a tendency to be insecure. He may have exaggerated how badly it ended between the two of them to spare you a little stress.

With that said and ex is a great person to talk to about current relationships (as long as you are still friends). They know everything about you and will tell you things that other people can't or won't. Also they are great for talking to about problems in the relationship because they have a different insight into your personality and have been in the same situation with you before. They usually are more serious and measured then friends who might just tell you to forget it and move on.

It may be hard but if you love him the perceived threat that you see is not a real one and should be forgotten. Maybe one day it could be a real problem but so could slipping in the shower or being hit by a bus but you can't live your life worrying about the bad that could happen because then you miss out on all kinds of good.Also when you start dictating who your partner can and can't talk to without a real reason you are crossing that boundary between partner and property.