Let's just clear up one thing here... She's the amazingly stupid fool for having an affair with a married man and lending him money. I can't even imagine being that STOOPID!!!
I'm sorry, but any woman who goes out with a married man and lends him money on top of that has to be INCREDIBLY desperate. There's no way on EARTH I'd do that!!!! Can you even imagine it? It's beyond my comprehension. Any guy I'd go out with would need to be showering me with diamonds and fancy cars, I may be blond but I'm not that dumb!!! 8-o
Anyhow, off my soap box. Time to stop ranting. Time to be completely logical.... regardless of what is happening with your husband (and I don't see a reason for him lying to you to get you to leave. His words and actions aren't indicating he wants that although I suspect he's feeling really bad about this and may act a little uncomfortable because of what she's doing)... so, regardless of him... holding your family together for your children shows you are STRONG and that you put your children and your family first. Don't you DARE let her sick games throw your logic off. You need to stay on the "higher road" and ignore the trash in the gutter. Don't let her manipulate you.
If you feel upset and uncomfortable, just nicely explain to your husband that it is upsetting you and you need to cacoon for awhile. Let him know you care about him and really appreciate that he's there, but you just need a little space for yourself. It's okay.
Go to the gym. If they have one of those punching bags go kick it and pretend it's OW.
There is no arriving, ever. It is all a continual becoming.