Is the OW's husband aware of the affair? I'm guessing no.
The first thing I would address are your anger issues. It sounds like you both have a poor way of interacting, and someone has to be the first to stop it. I would strive to never yell again, ever (unless there is a fire)! Eliminate all disrespect and anger in your marriage.
I see that you wrote that you didn't change anything after the last crisis. I hope that you do not make the same mistake twice. It is critical that you return to a different marriage than the one that you were in, or you will be doomed to repeat it. You can't afford to go out? Well, can you afford a divorce or an unhappy life? I know I'm over simplifying things, but you can find activities that don't cost money. Even if you just take a nice walk in the park alone in the evenings it would be a great start. Time together, ALONE, is critical. I know a lot of couples that only focused on the kids. Today, many of them are divorced or went through a major crisis.
For most men sex and admiration are what makes them feel loved. Sounds like these broke down for you. Yes, I'm sure there were reasons why the sex wasn't there, or where you didn't feel he deserved admiration. Unfortunately, I'd bet it's exactly those things, admiration and sex (or at least the promise of it) that your husband is getting from the other woman. In the short term, I would recommend that you provide these things to your husband (sex only if you are willing, but admiration certainly). I'm sure there is something you could admire in your husband that you can think of. I'd try your best for three weeks- no anger, be admiring, be alone, sex if you want. Let him know that you want a better marriage, and that you are willing and able to provide it if he joins with you. If he still is not willing to stop contact with the OW, I think you'll have to separate to get his attention.
