1) Marriage counseling - you both really need to see a good counselor, if he won't go, that might be a dealbreaker for me. He's gotten away with this for so long, he might not take you seriously unless you take some action, but the first step would be to insist on counseling.
2)See if he will attend SLAA (sex and love addiction) twelve-step meetings. He'll actually find out he's not unique, others struggle with these same issues and CAN be helped (I have a good friend who goes for her love addiction issues, but she has mentioned guys who are there for exactly these kind of sex addict behaviors).
3) Start reading about sex addicts yourself (Pia Mellody has some good books). I don't know for sure if this is your H's problem - maybe he's just a jerk or a narcissistic sociopath - but reading more about these things may help you figure out what you're dealing with.
4) Take charge of your finances. Make sure you know where every penny is, the status of every credit card, etc. Men who are addicts in one arena, may be hiding other things as well such as gambling, credit card debt, etc. Make sure you protect your financial future.
5) This is not about you. Your H told those women whatever stories he thought would get them to sleep with him. He would have been long gone if he'd actually wanted to be with one of them.
6) Think carefully about your own life - if you don't feel confident to tackle it on your own, what can you be working on so that you get to that point? I am not suggesting that you give up on your marriage - but no one should stay simply because they don't have a full life on their own. Develop your full life, with YOUR friends, doing activities YOU like - then you can decide whether your H still fits into that, and whether he's willing to do the HARD WORK to keep you in his life.
7) From here on out, trust your instincts. He's been gaslighting you for so long - now you need to start trusting yourself.
