Please Help: I Caught my husband in bed with my married friend in our house

I had just given birth to our second child and my married friend came to pay me a visit. She was supposed to stay for a week as she came in from Abuja and she was on annual leave from her work place.
Usually, I sleep early so I won’t be so worn out for the vigil my baby makes me participate in – One night, as usual I had gone to bed, leaving my husband and friend in the living room. Somehow, I got up because I felt strange a and went straight to my friend’s room, only for me to find the door locked.
I knocked and there was no response. I kept knocking and knocking still no response. I ran to the living room and my husband wasn’t there and something told me my husband was there. So, I stopped knocking and sat on the floor for almost 30 minutes, and they thought I was gone and they silently opened the door but there I was.
They looked as though, they should disappear. I could not scream, the only thing I could say was that I didn’t want to see any of them. My husband knelt down and started begging me and my friend just packed her things and left.
I don’t know how to forgive my husband even though, he has been begging me. Please what can I do???