My husband cheated! Advice...

My Husband of only a year has confessed he cheated on me while I was pregnant with our baby. I was heart broken! I couldn't believe he would do this to me he was do loving and sweet. He said he did it because I wasn't emotionally there for him. He said he had sex with a co worker one night when they were partying. He told me that it was a huge mistake and would never do it agian. I told him that I would forgive him but I keep on thinking about him cheating on me will there be a time where I stop thinking about it? I don't know what to do? Help!!