I know an SLE who told me about this girl he was TOTALLY in love with when he was young. In fact, he transferred to an out-of-state college to be with her. They were together for almost 10 YEARS. And then I guess he wasn't moving fast enough in the commitment category and she ended up dumping him for someone else. He said he never saw it coming. The way he talked about it made me think he wanted to marry her eventually, and regretted that he let her get away.

When he was telling me this story, I got chills and started to actually feel jealous (which is completely crazy, given that this happened when I was about 10 years old and we're all married to different people now, yada yada). But it was like I wanted someone to do that for me. Drop everything and change his life just because he was that much in love with me.
But I think that when SLEs really fall (in love), they can fall hard.