I have shelves and shelves of books full of advice on sex and relationships, but not a single one addresses turning a friendship into a romance. I know why, though — because it's never been done successfully.

OK, maybe that's not entirely true. I know at least two people who've pulled it off. They've been friends for years. They're getting married this year.

My first experience of trying to get more friendly with a friend was ugly. It was in high school. I invited a buddy of an ex-boyfriend to the grad “just as friends.” I'd been lusting after him for awhile, but knew his loyalty to my ex would preclude me asking him on an actual date. I figured I could play along with the “just friends” bit, then ply him with alcohol and take advantage of him. It worked (remember, kids: loyalty and alcohol don't mix), but even as we were going at it in the plush surroundings of his shag-carpeted van, I knew it was trouble. Sure enough, he regretted his actions by the sober light of day and, worse still, our friendship was never the same again.

Sleeping with friends is risky, even if you're both into it. Because, no matter how many times you say you don't want to screw up your friendship by sleeping together, you usually do. And, lucky you, since it usually doesn't pan out as a sexual relationship, you get two for the price of one — a screwed-up relationship and a screwed-up friendship. If you’re lucky, over time, the weirdness subsides and you can re-establish some semblance of friendship, but it's never the same after you've seen them naked.

Funny, though, because in many ways you'd think it would be ideal. You know the person well, there's less risk of the old diving-in-blindly routine, you are aware of, and presumably have already accepted, many of their faults; you know their take on relationships and have probably heard enough about past relationships to know what not to do.

But then there are the negative aspects: you know the person too well, there isn't the same blind passion driving the thing, so you don't know how the hell to make it go anywhere — their faults now affect you personally, and you know their take on relationships.

The female half of my friend-to-lover success story — we'll call her Nancy — insists it was great having everything out in the open. “It was a lovely, open way to get into things,” she says, adding that they used to joke to each other — while pouring their hearts out about their crappy relationships — that when they were 75 and finished with all the insanity they would get married. “We understood each other rather than judging. We shared more common ground.”

Makes sense. However, there is such a thing as having too much information. It's like backing in, which is always harder to control. And, when you've got inside information on what that person is like in a relationship, not only does it create dangerous preconceptions, it can also be tempting to use your knowledge against them if things get rough.

I once got involved with a very dear male friend after a particularly brutal breakup. During the breakup, this friend was an indispensable source of comfort and wisdom, so in many ways it made sense. This guy knew me at my worst and demonstrated his capacity for compassion, understanding and communication — certainly, a few of my favourite things. Unlike in the movies, where a comforting embrace suddenly turns into a passionate kiss, we just sort of stumbled drunkenly into bed together one night.

Then it got strange. First we didn't know how to say goodbye. Was our usual peck on the cheek to be replaced by full tongue action? Getting to know each other all over again as lovers was thoroughly confusing. Renegotiations proved too difficult. We cooled it before we destroyed the friendship, which was ultimately much more important to both of us. We’ve both gone on to other relationships, but that tension remained for years and left us constantly wondering: maybe some day when we’re 75 and finished with all the insanity....

Unfortunately, as I mentioned, there are few guidelines for turning a friend into a lover, or even more challenging — into a relationship. “When Friends Become Lovers” — sounds like a self-help book waiting to happen.

Maybe Nancy could write it.