I still feel at a loss how to warn him away without her 'undermining' what I've said.
It's really really simple.
You tell him it wasn't appreciated and that she does mean something to you so you don't want him taking advantage of little wobbles in the relationship. If that's the role he wants to play then he should shove off.
Then you tell her how important she is to you and that you don't want little wobbles in the relationship (they happen in all relationships) to mean the end. Tell her (and mean it) that you don't mind if she vents to friends, but she has to be careful of guys that are ready to prey on that condition. Indeed it is indicative of someone not caring very much for her, as he could do something to ruin a relationship she actually wants to go back to.
Ask her not to see him again because he is that type, or if you feel confident enough, then say you won't stop her but she should be careful. If she goes back to him after promising not to, or ends up doing the same thing as before if you let her see him... drop her ass. This is your life and no matter how much you care for her, she is doing you more harm than good.
You don't understand the depths of her social fear
Then get her a psychiatrist, or in contact with someone long distance she can talk to. Maybe an online forum of some kind. Or try to introduce other people in small doses. It is true that you'll have a hard time getting a shy person to suddenly like a bar scene.
I can only assume because she responded to his kiss.
Here are the facts: he wanted her and she wanted him. There is no her "responding to his kiss" without it. You will have to accept it and forgive, or move on.
The pertinent question is whether her desire for him is greater than her desire to continue her relationship with you.
I keep thinking of myself as Ross Geller in Friends,
If true, get out of the relationship. That was pretty unhealthy.
holmes
"...what a fool believes he sees, no wise man has the power to reason away.."(D. Bros)
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