what to do

well I have been married to my husband for 11 years and honestly I am at my wits end. This man is an excellent provider for our family. We have 4 boys 1 out of the house and 3 still here. I don't know if I should walk or give it one more chance. He has betrayed me time and time again. He cheats on me and I allow it because i have not left however this last thing has truly crushed me to the core. I haven't slept in days, I can't eat or sleep. I don't know what to do. My family is the most important think in my life. I  however am tired of fighting to save a marriage that for whatever reason seems unsaveable. I am seeking help for the marriage. My husband teels me time and time again" I will do better I promise ."  I feel he will hurt me again if I give him this chance. Our baby boy heard me asking him for a divorce and he ran down the street crying. He begged me to just talk to his father please don't get a divorce because that means we will not be a family anymore. He kept sayong please mom that broke my heart I told him I would talk to his dad. That was 4 months ago and here we are again backt to the same madness. I don't let the kids see me in my emotional state because I said I would try but what am I to do. My husband has been trying for the past few days to pleade his innocence to me, I can't trust him and I really want to.