What to do

u have been Married for almost 27 years.  I have 3 beautiful kids. 1 in college, one graduating this year from High Scooul and another a Freshman in High school. 2 Summer’s ago I found a Facebook messenger chat with a woman on his tablet and confronted him. He said he hadn’t done anything other than talk through the tablet and that he was sorry and said he ended it.  On Thanksgiving week this year my daughter overheard him saying something about someone being naughty and having his pants off. She was devistayed, rounded up her brother and sister and confronted him. He denied it all together and said she had been hearing things. I kept replaying it and confronted him.  My daughter had wY too much detail and I didn’t buy that she made it up. He said it was a girl that he had been talking to and helping out. I was pissed for a few days, but ultimately decided to stay and not throw away 27 years. Yesterday I discovered he has continued to contact at leSt a couple of women. Thoughts on how I handle this would be appreciated