Caught Husband With Maid…..

I am a 35 yrs old married woman who has spent 10 years of married life. We have a young maid for 3 yrs. Our relationship was nice till recently. Recently when I had gone out with my children and returned home a bit early as planned. My husband was alone at home. But when I came home I used my key to open the flat, I was shocked to see him with the maid in the bedroom. They were having sex. I slapped him and went to another room. When I questioned the maid, she told that she had come just now and my husband asked her for a sexual favor. Also, it was the first time. Even she is a married woman.
To my surprise when I questioned, again and again, my husband told that he did not have satisfied sex life with me and confessed that he became mad when he saw the maid alone. My husband denies having sex with her before. How can I believe this tale? He tells that he’ll prove to be a good man and will never try to cheat me.
Ours was a love marriage and he tells he loves me and does, not cheat me. Even I feel he love me and my children. But I am unable to forget what I saw in my bedroom.
He is ready to face anything and tells that he is clean except that only incident. I am confused and not in a state to believe him or leave the house because I have 2 daughters and my husband is showing concern for us. What should I decide? I am a homemaker and not a working woman. Can I give him another chance? How can I make him trustworthy after this incident? Will he be mine forever? I am in a dilemma and often getting frustrated. looking forward to good suggestions and guidance. Still, I have not come out of the shock and not in a position to decide anything.