@Coolbus,
I'm inclined to read this as a troll posting with a made-up story intentionally placing the husband in the more common wife's role, as the one who cooked, shopped, but lost the spouse's affection to an invisible internet suitor.
Regardless of whether it is... see a lawyer, draw up divorce papers with the great advantage going to you; that's the price of letting her explore her fantasy, and pressure her to sign. You keep the house, you keep the car, if there are kids, you get custody and she pays YOU child support, etc.
IF she never comes back, fine, you've got that base covered. IF she wants to come back, tough terms are in order: 6 months mandatory mental counseling/rehab, STD testing, and of course YOU would need your head examined to even consider it but hey, that's your problem.