You can't change her. You can change yourself.
Most of us here do not want to 'live in infidelity.' We don;t want to be with our WSes (Wayward Spouses) while they're cheating. Therefore, we lean toward courses of action that either cause the WS to end the A, which makes R(econciliation) a possibility (that is, not a sure thing), or we end our M.
Actions like telling the WSes family assume that outing the A will shame the WS into ending it. I'm not a fan of that action, because it's possible that the shamed WS will come back resentfully, in which case she'll probably cheat again or be a lousy partner.
But there are other options. You can simply wait a while in the hope that your W will come back by her own choice. Some people do that. I could argue that a lot of people do that.
In fact, what I did could be viewed as waiting for the A to end. I mean: like many BSes I knew something was wrong with my W. I asked if she was cheating 3 times, and she denied it 3 times - but I knew it was a possibility. Our relationship deteriorated, and I was thinking about changing, when she revealed her A.
IOW, instead of pushing her on her denials, I waited, and she decided to end her A and change from cheater to good partner, independently of what I did.
You control you. What do you want to do now? Do you want to wait and hope? Sometimes the WS does come back.
Do you want to force your W to really choose between you and om now? Eventually she'll have to choose, but you have influence over the timing. You can force the choice now - if you want to.
So what do you want? Once you decide, we can provide advice and support.
BUT - BUT - BUT
Even before you figure out what you want, it's important to consult a lawyer and get advice on your rights and duties, especially the financials. If your W is using your joint resources to fund the A, it would be good to stop the drain.
If childcare expenses go up because she's with om, and if she's working, I hope you want her to contribute to paying the costs.
IOW, lawyer up now. Today.
AND - AND - AND
You need to take care of the health of your kids and yourself.
Is she carrying and STD? You and she need to get tested. Today.
If she's going back and forth between you and om, she's increasing the risk of infecting you and your kids. That should stop.
If you're sharing a room, that should stop. She's a danger to you.
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If all that sounds too difficult to do, you need help, and I suggest reading The Simplified 180'.
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Once you've digested the advice you've been given, come back and tell us about your reactions.
[This message edited by sisoon at 1:51 PM, April 22nd (Wednesday)]