Do you have any friends who live in your state who've been trough a divorce? Who could recommend a good divorce attorney? Sitting down to discuss exactly what goes into a divorce proceeding and what responsibilities your husband has to you (alimony, child support, etc) might impact your decision. Tree are definitely the emotional and moral/spiritual aspects to consider, but also the practical aspects. Each state has their own laws. He may owe more money for alimony based on you being a SAHM, number of years you were married, how much assets you have, the affairs.
If you have proof of the affairs then get it together. After you meet with the divorce attorney you'll have a better idea what your heart really wants.
Then tell him you're going to attend marriage counseling and that if he'd like to stay married he needs to attend with you. Give him a few months to come around and yourself a few months with individual counseling to see how you feel then.