" i'm 31 she is 28, one kid each from other partner.."
OK, you guys are all grown up and have had your share of both joys and dissapointments.
You are still at the stage where this is sticking in the pit of your stomach. Time will heal that, however this plays out.
I feel your pain. My advice, (since you asked
) ask her straight out - "Promise me this will never happen again, for any reason." If she even has to think about saying 'I promise'. Then my man, I think you need to leave. If she says 'I promise', then you have to take it as that and move on with your life. You can't live your life waiting for her to break her promise. If it does happen again, then obviously you leave, no questions asked.
I guess my final thought is you seem to need something to allow you to move forward. Let it be the answer to that question.
Good Luck