If you date a well Trained slut girlfriend -- be sure to keep her a slut -- as a wife. Slut wives are the only kind of wives to have. Don't let that early Training go to waste. Share often, and USE all her holes! Preferably, simultaneously.
I was very lucky, on my second date with the woman I ended up marrying, she just told me, " just to be upfront and honest, I can't possibly be satisfied with only one man." I looked her right in the eye and said "excellent, I hope to be allowed to watch." She kissed me and said "we were made for each other."
a wife should be collared and shared.. you're right, start her training early, when you're dating.. you know what you want, make the effort to train her properly. when you get engaged, make it a prerequisite that she continues as your submissive to be shared as you see fit.