I would initially be hurt but it is past and not the "truth" of the matter either then or now. I would either move forward or decide I didn't want to stay married to such a person.

What you husband told her is not about "the marriage" but his own idea of what the marriage was about at that time. I would probbly tend to laugh at it or I might be a bit more angry than hurt. He has a problem and he's telling someone else his troubles instead of me. But he can't tell her about "you" because only you know about you. He can only tell his take on things. Too, your marriage is you and him; without you in the discussion, there is no truth there, no "whole"/marriage. Together is the only way you could tell others about the marriage between the two of you. All he did was behave in an immature fashion, crying on somebody's shoulder instead of working on his problems like a man.