Do you have a guest bedroom where you could sleep? A basement room? A sofa? You taking the initiative to sleep elsewhere will be setting a kind of boundary: You're not willing to continue to pretend that everything is okay when she is likely stepping out on you. If you are meeting her emotional needs, now is the time to draw back. This will be much easier when you're not under the same roof.
Ahoy, thanks so much for your suggestion. The problem is that I am pretending everything is OK because I don't want the kids to be upset and I don't want to be the cause of further strife in the home. I don't want the kids to blame me for the breakup of our family. And my moving out of the bedroom will be a visible concrete step in that direction. They don't know about the infidelity, but they see the breakdown in our relationship. Moving to another room will make me look like the instigator. I would not even know what to tell them if I did.
I know that by not setting boundaries I am probably not respecting myself.