i know what it is like to keep trying to build that trust (T, others...) and for them to have such an inapropriate response is really horrifying. Like everyone is saying, M is the one who messed up. M needed to say something to the effect of "I'm really, truly sorry this happened to you. I am. And I am also sorry, but I am not (ok, safe, wanting, able) to hear more. Thank you for having trusted me to this point, and hopefully our relationship can take on a new aspect" then see how that sits with you both, take time with it, etc.
Sad thing is very few are that skilled in relationships - and those of us who do know may not be that skilled when it comes to saying it (points at self).
In the end, what i want you to hear is YOU ARE GOOD, CLEAN, OK, ABLE TO HAVE LOVE, AND WORTHY TO HAVE LOVE/ BE LISTENED TO. Nothing changes that. Nothing.
(((((((((((((Zoo))))))))))))))