Ovrrnbw, I'm not sure about any legal considerations but if you're both owners of the nice car then I don't see why you couldn't take it and drive it yourself. Does it have to happen secretly or so soon though? It seems eventually your wife will come home and you could claim the car in your own driveway. Or you could text your wife and ask her to bring the car back so you can drive it and if she says no, you could either tell her to start paying for it herself or you'll sell it. If it's leased that might be a different story. I know your wife is acting crazy but the first option seems to be to get the car in a collaborative manner. If that doesn't work then you could take more extreme measures. I'm not sure how others will look at it but I agree it's time to take steps towards stopping her from taking advantage of you.
I don't know enough to comment about the car wash issue. It sounds like you pay most of the bills. Some states don't allow for legal separations but if yours does you could try to file for a legal separation to get everything in order. Or you can just stop allowing her to take from your salary by removing her from your accounts or checkbook. That probably won't go over very well. I imagine she'll lie and do things to stop you. That's why a legal separation would carry more weight but unfortunately it's not an option everywhere.
I hope you do something. That is really unfair for your wife to be running around with another man and yet living from you financially. Perhaps she'll be forced to make better decisions if there's financial pressure, or she'll just ask the OM to help out. I have no idea because I don't know enough details except that it sounds like you're doing the right thing.
