My 2 cents. I think you are right that this is a big opportunity to show your H that you have changed. I think that resisting, rather than celebrating this possible work ay have the following results:
1) Showing him you "can't change". 2) Undermining his role as a strong man and husband, as an equal partner. 3) If he doesn't work, this wil only contribute to his depression. 4) If you don't risk it, you'll just be hanging onto insecurity, rather than overcoming it. 5) You will demonstrate that you don't believe what he says. 6) You will make OW more attractive. 7)- 1,000,000,000) I bet you can fill them in...
My suggestion would be to ask for a do over. Tell him--and be--excited about this wonderful opportunity for him. Tell him you fully support this choice as his choice. That you are proud of his efforts to found work, and are not at all surprised that his company would want such a great guy back. That you see this as an opportunity for you too--to show that you trust him, to work on your insecurity. that you are sorry you rained on his parade. Explain that you expect this may be awkward at times for both of you, but that this doesn't need to be a stumbling block in your R, or in his career. But, you'd like to do some brainstorming around likely scenarios. Do this is a security-building exercise, not an insecurity-needy-help me exercise. Cheer for your H, come on, he's doing this for you, for himself as a man, and for your R.
Think about someone in the past who you dated briefly. Aren't there cases where it was really just over--nothing there? The more you are with, and for, your H, the more he is likely to be repulsed by OW.
You are strong. You two are strong. You can do it! It is a wonderful new chance on the horizon in so many ways. I'm not saying it won't be hard. I understand your worries, your dismay, your pain (how could he think of doing this to me)... But, I really think is in a different place with respect to OW than you. Don't let *her* control your lives.
OK, maybe 10 cents, rather than 2 cents.... You may have noticed that LL threw my last 2x4 right back at me :-)
