I'm older than you but can relate to many of the issues you're dealing with! My H also hung out way too much with his friends, was drinking a lot, doing drugs, and viewing porn. He was even signed up at several cheater websites! He always denied everything, even when proof was there in black and white. He also told me I 'wouldn't want him if I knew everything'.
When serial cheating (multiple partners) is involved it's even more daunting to try and work it out. My H only confessed to cheating with one person but it turned out there were several others. I got a few weird phone calls and he'd always tell me that "people are jealous of us and trying to destroy us", but it turns out they were telling me the truth!
I'm sorry for your pain. You will find your way through this mess, just hang in here.
the lies are continuing even after all this.
I seriously doubt they are going to stop either. You need to worry about you and the kids and let him twist in the wind.
The drama here needs to be cranked down about 1000 notches. Nothing productive is going to happen from contacting all these OW. Focus on you and the kids.
The Healing Library is in the upper left hand corner in that little yellow box. Click on that, click BS FAQ, topic 11.