aw man this broke my heart. You sound like my mom...except she stayed for the sake of the kids (my sister and I) and I see how empty and beaten down she is when I look in her eyes. I have my own trust issues so my advice is very biased. What I can tell you as someone who grew up with parents in a similar situation as you and your partner, is that I WISH my mom had the courage to leave. Your kids will sense the disconnect whether you want to admit it or not (if they don't yet, they eventually will). They will learn of the affair one way or another and what you do now will shape how they value intimacy. I look back at my parents fights and how my mom sacrificed herself for her kids and I feel so sad knowing that the decision she made actually hurt us more than it helped us. Being a single mom has got to be one of the most difficult things in the world, and for all I know, we could have ended up suffering way more than I could have imagined (mostly financially). But, if you have the financial means, then do your kids a favor and teach them that a TRUE partnership is one without deceit. I wish my mom had taught me that. Good luck to you. You come off as a very sweet person and I truly hope that whatever decision you make is the best one for you and your family.