Ernst, firstly it's not possible to get a UK divorce:
"Either party can apply to the court in England or Wales for the marriage to be dissolved, provided one or other is domiciled here or has been habitually resident here for at least one year before the application to the court is made. It is not possible to start divorce proceedings within the first year of marriage"
There's some info on the procedure here in Switzerland:
Swiss Divorce
From my point of view I think you should separate - what future would you and your children have living under "that" cloud. However, I think the mechanics of divorce are way down the list of priorities. That's a knee jerk reaction to what he's done and there are more important things to think of now.
I have a "Relate" book about coping with an affair which helps put some of the feelings you are now experiencing into perspective. If you PM me with your address I'll send it to you.