How can I make my mom stop comparing my ex-husband to my new husband??

I love my mom, I really do, but it's gotta stop. I've asked politely, pointing out that I've been divorced for nearly 2 years and I've happily moved on and remarried. Here's the deal: Actions, viewpoints, and expressions of my new husband are constantly compared by her to what my ex would have done/thought/said. He's not even in my life anymore, so there's no proximity that would be spurring on this obsession. When we talk on the phone (we live in diff't states), she feels the need to verbalize her compare and contrast exercises. I can't even go 2 weeks without this taking place at least once in a phone conversation. The last time I asked her to please stop doing that she acted upset. Well guess what. I am upset and tired of this. I don't want to CONSTANTLY be reminded of my first failed marriage through her unsolicited observations. How do I make her stop???