I Need Relationship Advice..

I Am Married with a 2 year old little girl. My Husband has cheated on my numerous times.. We are just now moving into our new house and an old boyfriend who I happen to work with started "Sexting" me. Sending Nude pictures etc. I fell into temptation and I sent one picture back.. I instantly regretted it.. While trying to figure out how exactly to tell my husband what happened he went through my phone and read everything a few days later. He didn't care that I regretted it or that I was deeply and sincerely sorry. He wants a divorce because I was for the first time EVER unfaithful. Keep in mind he has had Sex with other girls while we were married multiple times and I never left. I lost my virginity to him and have only had any sexual relations with just him. I don't know what to do 😔