Why living together before marrying is a bad idea
This may offend some people, but it is merely an opinion based on some statistics and from viewing real-world relationships. So, please do read with an open mind, even if you do not agree with the points made here.
Statistics demonstrate that most people who cohabit usually don't ever marry, or the marriage usually ends in divorce within a very short time. Many individuals (especially women) are doing themselves disservice by living with a partner in a non-platonic relationship, without being married. Some people argue that marriage is only a piece of paper signed and or meaningless.
The part about being a piece of paper is partially true. The truth is when someone marries someone it's much more than that! Individuals are expressing to each other that they truly love each other and want to spend the rest of their lives together.
One of the reasons divorce rates are high amongst people who have "shacked up" before marrying is that they anticipate that things will change after they are married. Some people believe that ultimately being married will all of a sudden make life seem perfect and the other person will change for the better after marriage. The reality for most is that it does not happen. This disappointment is ultimately what makes many individual to end the marriage.
Many people who living together never ending up marrying because many men simply don't feel the need to. If you look at it from a man's perspective, he is basically getting everything (and probably more than) a wife would give him without marriage, so why should he even bother?
This is a comfort zone mostly for men who live with women they're not married to. There is no actual (or legal) commitment. He can leave whenever he wants with much less guilty feelings than if it was his wife. Women are most likely to want to marry as she knows in her subconscious mind of the fear that he may pick up his bags and leave at any time without too much emotional hassle.
This may sound cruel to some women, but there is a difference on how live-in girlfriends and wives are looked at by men. A man is much less likely to leave his wife than he is to leave his girlfriend. Men do leave their wives of course, but for the most part, men are much more likely to leave their girlfriends more easily and without guilt. It's a similar principal for men cheating on their girlfriend verses their wife. Again, some men cheat on their wives, but a man will feel less guilty about cheating on his girlfriend then his wife.
The best solution is to not living together with someone if you are looking for a possible marriage partner. This will benefit women more than men, but it helps the marriage overall for both partners.