Just a view from outside ...
The Bad
1. It has happened. It's out there. There's nothing that can turn back time.
2. Your relationship as husband and wife has suffered many years. it will take time and a lot of will to work to improve things.
The Good
1. You still love him
2. IMO, he still loves you
3. And he wants to stay married and will do anything for the family
Call it opportunity, temptation, curiosity or plain horny. He could have sought emotional refuge in the arms of another woman. Instead, what he did was to have an avenue for his physical urge. And if he's level-headed and follows Big Boss' Tip No. 4, then really he is not in love with the working gals. He still loves you.
Bottom line is you BOTH must want your marriage to work.
It means forgiving as hard as it is. It means putting effort and time in re-building.
Not sure how the daily sex is working out for you. Seems like you have swung from one extreme (a few times a year) to the other (banging everyday!) I mean, hell if you drain him dry every day, there's really very little urge or ability to shoot any more elsewhere. Just beware of overkill
You can move on and gradually bring intimacy back.
Intimacy is not just sex. It's sharing your dreams together - the kids' future, growing old together, talking walks, dinners, being together without saying anything. Go on a holiday. Catch a concert.
I can imagine your burning desire to know if your husband will change for the better or not. while it's not wrong to seek opinion, sometimes hearing too many perspectives is confusing and will negatively hold you guys back from progressing. Letting friends, relatives and lawyers know IMO is really counter-productive. Confide in one or two trustworthy ones and yes anonymously venting here is OK.
When you got married, you made a vow to stay together thru good time s and bad. This is but one of those bad patches. I'm not belittling the indiscretion and betrayal of trust, but life can have harsher issues and much worse patches. Believe that your marriage is stronger than this episode. Believe that if you both want it, you can survive this.
The answer to your question really depends on you both, you write your own ending in your story.
best wishes
