Friendship Breakup

Breaking up with friends is weird. When your friends try to get back together with you it is even weirder. Allow me to share a little story with you, and by little I mean long and drawn out and potentially boring.
In high school I had this friend, let us call her Joy for argument's sake. We were all friends, we hung out and participated in self-destructive teenage girl behavior. In 8th grade or so (I am a little foggy about the specifics of the relationship)she started dating this senior. Now this sounds cool. But in fact it was not. This guy was NOT cool and well he was grey(and he was way into Star Trek TNG). However she did get to go to the senior prom in 8th grade.
So I don't know, maybe they dated for a while, then stopped.
Somewhere along the way, Joy got forbidden to hang out with us (because of afore mentioned self destructive behavior) and turned back to the "chorus people" and back to the grey man.
So I don't know - flash forward to college and she moved to Boston for a while. I am not really sure what happened here, I know she "spread her wings a little bit." But then she left Boston after a year and returned home. Got re-attached to the man o' grey. And was engaged at 19 or 20. They got married a couple of months after she graduated from college. And she is 29 now with a kid in kindergarten.
So that is that for the backstory,
Now let me take you to last summer.
Jon and I had a little BBQ to send ourselves off to California. Joy, husband and kid come. She has told me in not so many words that she wished she had waited to get married and have kids and I am sure (IMHO) she is a woman who lives with many regrets. I may be wrong but that is kinda what I get from her. Also her husband is Creepy. Yes with a capital C.
So that was the last time we saw her. When we moved out here I sent out change of address cards and shit. I prefer to communicate through email. I don't like the phone. I know I put my email on the COA card. I didn't hear from them, ok whatever. I send them a holiday card and tell them about Maria's baby and stuff. Nothing. So I am like fuck 'em.
When jon and I were home and we had our little baby shower many people asked where Joy was because she was sort of a fixture at those MA things. I guess we had a falling out, I said. Fine. I mean, you know, you grow out of people at some point, maybe. I wasn't losing sleep over it.
So then maybe 2 weeks ago, I get a phone call from the husband. Thank God I am psycho and screen all my calls. He says they moved into a new house and wanted to make sure we had the info, and to call him back, yeah, um no.
Then this week I get a card from Joy, in the mail. And it is like this "I'm-sorry-we-broke-up" card. It shows two little cartoon figures fuming at each other and then the next one apologizing and a "let's be friends again" inside. And saying that Maria's baby must be big by now.
I am torn how to reply.
At this point I feel like they missed too much. Also at no point was I aware we were fighting. I don't want to tell them about the babies mine or Maria's 2. I don't feel like they deserve to know. Isn't that shitty and selfish of me?
I could respond and be like,
"hey guys I wish nothing but the best for you and your family, but let's not kid ourselves. There is no friendship here. Take care of yourself and be happy and well"

Then the other part of me wants to just ignore it and pretend we moved.

I guess I really don't want anything to do with them anymore. I mean history can only go so far and they both have a selective memory about things. And I think one of the reasons Creepy wants to be friends is that he thinks we will be swinging with them at some point. Excuse me while I barf.

So I don't know. Does anyone have any advice or any similar experience. I think by my inaction I have already decided.

Why do I even care?