Why do you want to know? What lie can he ever tell you that you will believe or will be good enough?
I can tell you - you say multi??? Then he was enjoying the chase of the new and shinny toys. He did not care if those women were married, mothers, or feel for his attention of affection.
He just loved the action of the new smell the new feel. Once he got it and used it up he moved on to the next one.
He most likely came home many times after being with someone and then was with you, and seemed even more energetic than before.
What do you want to know? Why could he do this to you? It had nothing to do to you, he was stroking his ego on the fact he was having sex with different women and getting away with it.
Go ahead and confront him but know that the lies that will come to you are all in an attempt to win and keep you under control and him not lose.
You want to win and get the piece of mind you need and deserve?
Leave without notice, take only what you need to move forward, never look back. File for divorce, never speak to him as much as possible use the lawyer for communications.
Never give him the attention he will seek.
Never give him the control he will attempt to gain over you.
Never give him the satisfaction of knowing what you know.
Win in knowing you took the attention, control and knowledge away from him and he will think about that and need it for the rest of his life.
You choose the win here.

Thank you for your comment. If I could just leave I would. We have a 9 year old. I guess I just want him to know that I know and that I fully expect him to spend the rest of his life making sure someone doesn’t treat his little girl like he has treated me.

He'll know that you know when you file for divorce.

The fact that you have a 9 year old daughter, who probably suspects something is up with you two, is all the more reason for you to go to a divorce lawyer, right away, and you and your daughter get the heck out of this situation.

Don't worry about the - I want him to know that I know - Who cares at this point? You and your daughter need to get this guy out of your house, get child support and alimony for you, and get rid of this guy. Protect your daughter and file for divorce asap.

I 100% agree with both responses here.. why give him the courtesy of telling him the truth?? He obviously doesnt feel any need to reciprocate those feelings.. focus on moving forward and onward.. keep your daughter and yourself as the priority now.. fuck him and his secrets.. dont dig.. dont question.. dont give him the chance to sweet talk his way back into your heart.. common courtesy doesnt have a place in this scenerio.. all that matters is you know.. and what you plan to do now that you've been given that gift of knowledge - details will really do nothing more than cause more pain at this point.. try to keep your focus forward.. and as much as it hurts.. be grateful you know what you know.. instead of continuing to live in the dark..

I don't think it matters a whole lot how you found out. The point is, you found out. My husband was doing the same thing. I started figuring out something was wrong when he password protected our laptop. Things started to unravel and he ended up leaving me for another woman. My infant daughter and I were left alone. When I confronted him, he denied everything. I had to take whatever proof I had to my attorney. It is a devastating situation, and I am here for you to vent whenever you need. Thank you for staying strong for your daughter. He can find out after your attorney serves him, but I do think it would be important to approach a conversation before that happens...

I’m so sorry to hear about your situation. I am worried about him denying everything and even though I have proof, the way I obtained it is basically illegal. He is also keeping things from me and putting money into other accounts that I have no knowledge of or access to. I do feel I need to have a conversation with him before he is served. But I can’t tell him how I know or provide proof to anyone without incriminating myself. I live in a no-fault state so the court doesn’t care about his morals in the slightest. His family has money and I’m worried they’ll stop at nothing to make me look bad. So I’m basically freaking out.

Just talk with a lawyer. I am not an expert on this but if it is a family house if you leave you may lose some rights. I wish you all the best.

I'm not married but we live together . only a year and a half, so I'm not saying "I know how you feel" that being said. I have the same problem on a smaller scale. I snooped. Daddy always said"you go looking trouble...you gonna find it" live sex chats...apps for hidingphotos...who knowd what else since he guards his phone like fort Knox. I am incredibly hurt and want him to know I know. Snooping is bad. We agreed. Live sex chats are cheating. We also agreed.trying to decide if I'm gonna throw myself under the bus or quietly trudge away

Well I spilled the beans. I got into a private email and found he has an Ashley Madison account. Even saw where he chatted with someone online saying. He was looking for sex because his marriage sucks. I hate him. 3 kids and careers. All for nothing. 18 years wasted. And I told him I hacked his account. I don’t know what is or isn’t legal, but I don’t care. I got the info I needed. But what hurts is that he doesn’t really want to be sorry. He’s been verbally abusive for years and I’ve become isolated from people socially altogether. So I’m totally alone. Just as he likes it. Desperate for relief

My husband wants a divorce and I didn’t do anything that is on the “do not forgive” list... he simply thinks we would be better apart.. which I disagree with ... but the point is.... if you want a divorce then start the process and if he asks why .. tell him you just think you’d be better off apart ... maybe one day you can tell him why.. but I think for now keeping the ace in your pocket is a good idea...