Thanks everyone. I just can't get over the feeling like I've royally messed up. It really is something I had planned on bringing up with him someday. I wanted to bring something up that my DH shared with me that I really wish he hadn't. Ironic, huh? Even my T agrees, I could have gone a lifetime without knowing what my mother shared with my DH during their conversation the other day. Thanks mom (and DH too), I appreciate it.
What's done is done. I do know that it's better that he knows, but it still hurts too much right now. Only two people in the world know and that's two people too many as far as I'm concerned.
Thanks again.