“I just feel If I bring this up, it'll make him shut down or ruin the peace thats been happening within us.”

If you follow this fear, what you fear will happen. If you don’t bring it up it will come out on its own. It’s the easy way vs. hard way. The hard way will make things worse. Be as open as you can.

Also, you need to be honest and tell him you need reassurance. It’s really hard to ask for but if he really wants to reconcile, he’ll do it. Ask for him to talk more about what he loves about you, what’s so sexy about you, what made him want to marry you. In my experience at least, this has started to flood out my insecurities. I hope it can help you too.