I've been living with my fiance for about a year and a half now. I moved in with him after we'd been dating for 4 months. We got engaged on our 1 year anniversary (so, had been living together 8 months)

Like everything else, it really depends on the individuals and the relationship. I came close to moving in with other boyfriends during college and I'm glad I didn't, as I know it wouldn't have worked out.

Before Mr. Ginger and I moved in together (well, I moved in with him, he owns our house) we had to have a lot of serious talks, including.... what's going to happen if we break up. It wasn't fun to think about, but I'm glad we hashed it out, because if (God Forbid) something does happen, we each know where we stand. We also talked about things like... are we "just" going to be living together (kind of like roommates dating) or are we "Living Together" as in the Next Serious Step sort of thing. Talked about finances, living habits, what we considered acceptable and unacceptable, etc. I think these are extremely important conversations to have. They aren't always fun, because you just want to be nice and easy-going because you love the other, but when it's 6 months later and you're arguing about who's going to do the dishes and who will shovel, you'll wish you had!

As far as whether living together leads to not getting married, or less successful marriages... again, it depends soely on the couple. For us, it made us realize even more that we did want to be married. But I can easily see how it could swing the other way.