It really makes no difference in the outcome of a relationship.
Everyone has their own belief system or moral code. Some people follow the tenants of a religion and others choose celibacy for tradition's sake. Life is a (personal) journey!
I've known couples who didn't have pre-marital sex and I've known couples who did and they both ended up divorced or unhappy.
No one ever filed for divorce because they had premarital sex!
There was usually a "deal breaker" committed or incompatibility issue.
The top 3 reasons why a marriage fails in my opinion are:
1. They (chose the wrong mate) for themselves.
2. They got married for the wrong reasons.
3. They grew apart over time and stopped wanting the same things.
Truth be told when it comes to love and relationships most of us (fail our way) to success. Rarely does someone hit a homerun their first, second, or third time up at bat. If this weren't true we'd all be married to our high school sweethearts! With failure comes wisdom.
Having or not having sex won't prevent having your heart broken.
If something doesn't feel right to (you) it's probably not right for you!