That would bug me, too!
I resolved not to discuss my boyfriend's ex anymore and they are still friends remotely after 3 years since they broke up. He understands that I don't want to meet with her or be friends with her, but that doesn't mean they can't exchange the odd email, conversation or maybe even a lunch together once every blue moon. There's no way he's going in her direction, because he is so far in my direction that I really don't concern myself with why they talk or what they talk about....as long as it's only talking (about her dog and her sick father...you know, the kind of things that friends are wont to talk about).
I hate that he is still friends with her based on principle (and she is not very attractive to me, but I guess he was to her...see where I'm going with that?) but it has caused the worst fighting in our wonderful relationship.
You trust him and you love him. Enjoy your wonderful life and don't let this thing eat you up or you will both lose something wonderful. Like chipping the paint off a new car. It's a shame to lose something so rare and sweet.
If you need to, do some soul searching of your own. Do things that you like to do (alone) and wait it out. The feelings will go away as you realize how much you love him. What will make it easier is if this other woman stays out of the picture as much as possible. He loves you and won't let it come between you and him.....just find a way to purge the sad (insecure) feelings. You are HUMAN. Loving him with all your heart will help, cause it sounds like he really loves you, too. That is very therapeutic.
And yes, they broke up for a reason!!! Never forget that. Who cares about his past. Care about the present future.
Anyone in their thirties has resolved to the fact that for everyone, there is someone out there that we loved and just couldn't have. If that is the case for him, the bottom line is still the same...it's OVER in his mind and hers. Don't worry and enjoy your husband....he will be good to you and that counts for a lot!!!!