An attorney can request ANYTHING in a separation agreement no matter how outrageous or unfair. If he SIGNS it, he’s bound to it. YES he needs a good lawyer and he needs one now. 401K contributions-I don’t believe-matters in the income. It is gross income. If she is the dependent spouse (she make less than him or doesn’t work) then yes, she can request alimony and may get it.
In North Carolina, each party is due 1/2 marital asset and 1/2 marital debt regardless of status as part of equitable distribution. These items are negotiable in agreements though. If she is having an affair, and it can be PROVEN, then she is not eligible for alimony.
Tell him to get a good lawyer. They may investigate her for adultry (private investigator). Yes, it will be expensive, but he can’t afford not to do it. If she is moving on with another person, then so be it, but he doesnt’ have to pay her to do it.