You shouldn't be doing anything that compromises yourself. Giving up the bed is a great example. You shouldn't sacrifice just because she is the cheater. Also, how is she going out of town this weekend? Is she using marital money? You should be refusing to pay for ANYTHING that is enabling the affair.
Update:
I told her last night that I will not be giving up the marital bed. I told her she abandoned the marriage and I won't be the one to move. She says she may just move out (to her father's other house). When I told her she will need to start getting the kids ready in the morning she says, well, she'll have to stay at our current house then.
As for the trip, I asked who's paying for it and she says the OM is (how could she pay for it when we're low on funds, she says).
I read your story, btw, DMB. It's quite inspiring!