My husband just came clean about cheating on me.

My husband and I have been together for 7 years, Married for 2. Last night we were laying in bed and he told me he had to confess something to me. He told me that 3 years ago he cheated on me with a co-worker she gave him a blow job. And after that happen he knew it was wrong and knew he wanted only me and a year after that he proposed. I feel sick to my stomach because he never told me this I feel like the relationship is a scam. I love him but knowing this makes me think what else is he hiding. I told him I needed time to process this. What should I do. I'm at lost.