What to do when you know your husband/wife is having an extra-marital affair?

Get the details, find out where the problem lies, try to correct the problem and make the best of it.

oh you KNOW you love it

Make sure they KNOW that it is not going to threaten your basic relationship..
Find out WHAT you are NOT providing them that they ARE getting from the affair(s)...
Support them in their needs/desires and let your partner know that you love them and want them to be HAPPY and fulfilled, and are willing to do ANYTHING to help make that happen - even supporting their need for affairs...

Ask her if it's a woman. If she says yes tell her to bring her home 'cus you wanna meet her too. If it's a dude...well I got nothing I'm sorry man

Divorce or beat senseless with a trenching-spade; depends how much you want to pay.

It happens maybe because you are not doing your job well 😂

Well you can do a couple of things you can see if your spouse wants to go to counseling or you can start gathering evidence so your lawyer will have everything they need I went with the gathering evidence I had so much evidence by the time I actually filed for divorce I got custody of our kids on the first go-around.

Confront them.

ask her to give you all the details when you are in bed together. i bet it will turn into some incredible love making between you and your wife. maybe when she feels comfortable she will let you watch her with her boyfriend.

You leave..

You have to decide if that's acceptable to you. If it's not, it may be time to move on. If it is, bring it into the light so you at least know who and when and if you need to watch for diseases. Either way, you need to talk to them about it and work out YOUR future.