OP, it's not really about what any of us would do, it's about what YOU want. If you had lots of money, would you walk? Or would you still want to try to work it out? Only you know if this is a deal-breaker even if he was desperately sorry.
I heard some great advice once, about making difficult decisions. It was that you should make a decision that you can live with over time. Assuming he is cheating, you're at a fork in the road of your life. Imagine being 60,70,80, even 90, if you'd stayed and if you hadn't. Also, the missing piece of the puzzle right now is that you don't know how he'd react if you told him what you found. That is, if he'd be sorry and trying to save things, or if he'd be nasty and/or tell you there was something else.
Only you know the overall quality of your marriage. In one way, it seems crazy to throw everything away over a few shags, if that's what they were, and I think there is a question over how realistic it is for everyone to remain sexually faithful over many decades of marriage. On the other hand, I also understand completely if someone feels unable to move forward in the relationship and has to call it a day, and I think that's completely reasonable. People vary so much. Some are able to get past it, reasoning that this isn't the sum total of their marriage, and others dump the person immediately and never look back. I haven't been in this situation, so I don't know what I'd do. I think almost all of it would depend on how he reacted to being discovered. Some couples have said they worked through it and had a better marriage after. For others, it was the beginning of the end.
I think you need to talk to him.
Try to get a job if you can, anyway. You're very vulnerable, being a SAHM.
Sending hugs 💐 No one deserves to be the victim of infidelity.