Among other things, marriage is a contractual obligation between two people. Part of that obligation is monogamy. Another part is fiscal. If someone begins thinking about adultery, then it's time to end the marriage properly, with a divorce. At that point, the property can be distributed equitably.
Once a person cheats, I think that they've broken that contract, and at that point, forfeit any claims to property.
It's that simple, when you cheat in a marriage, you SHOULD lose everything.
Mark
Nope, that's completely unfair, and gives way too much credit to a non-cheating spouse (in other words, it assumes their hands are clean, and there's no reason to take that for granted).