You've just had a blissful romantic weekend away together and you have a lingering kiss goodbye at the front door early on the Monday morning. You head home on Monday night and the flat's empty, he's not there, half his things are gone and there's a scribbled note on the table: "I'll come and get the rest of my stuff tomorrow." All of a sudden your world is turned upside down.
Questions you need to ask yourself Did you really not see it coming? Where you saw a romantic weekend away, was he seeing the swansong to your relationship? Did you bury your head in the sand and ignore the distress signals he was sending you? What was wrong with your relationship? Did you ask too much of him? Did you ever really talk about what you both wanted? Did your 'foreward planning' for your future together scare him off?
What you can learn from it Nothing is set in stone. Relationships need work and effort and you need to be on the look-out for any signs he's not happy. Communication is vital if it's going to last: if you can't communicate with each other you won't ever know what the other is thinking.
But... Don't be too hard on yourself and don't go too far in your analysis of yourself. You can learn a lot from this split, but don't go as far as to blame yourself entirely. Someone who leaves you high and dry could well just be low-life, so don't waste any more time on him: once you've taken time to reflect, don't look back!