The concept of banning pre-marital sex is archaic. It comes from a time of objectification of women, and prior to our ability to control reproduction effectively. Logistically and practically, it's no longer a necessary aspect of society.
Married couples fight basically over 3 things: Children, Money and Sex.
The three things are fairly easy to solve if you do enough work beforehand.
1. Establish if you want children, how many and when, and take parenting classes before children arrive, so as to have a common ground to fall back onto when you argue about child raising.
2. Run your marriage like a business. Personal finance can be very emotional, but if you discuss big investments and those small investments that accumulate into big ones unemotionally, you can overcome this.
3. ******** like rabbits. For some people, sex is an incredibly deep bonding experience, while for others it's just sex. Some people want it everyday, and others want it once a month. Establish sexual compatibility before committing a sexual exclusivity pact with someone. You can everything BUT vaginal sex to establish it, but it needs to be established. Divorce is expensive, the back seat of a car is cheap. (Seriously, go to any newlywed forum, and you'd be surprised how often this comes up)
While I respect someone's wish to wait till marriage for sex, that idea is really outdated. I used to think that way, until I went to college. My question is what if the person is really terrible in bed? Now your stuck with them unless you get a divorce. You're better off to get some experience before marriage and yes, sex is very important key factor in marriage.