Should I tell the womans husband that she and my husband have been secretly talking on their cell for 6 yr?

My husband this woman and I were all friends and worked together. I found out about 5 yrs ago that he was secretly texting her. I told him it was her or me and he fired her and told me he ended it. Now 5 years later I find out he has been secretly talking to her on the phone. He says he needed someone to talk to about his fathers death and that nothing physical happened and that they never say each other just talked on the phone. He professes his love and wants to stay together. I have been married 24 years at the age of 23. Any suggestions of what to do. I have 2 kids 15,and20