Girls like putting their heads on guys shoulders or chest because of security, so why mine?

A girl I used to like, We'll call her Lauren, wind up getting a boyfriend a year or two after I told her I liked her...but one day when Lauren was really tired, Lauren laid her head on me, and wound up falling asleep on me. Now, if she had a boyfriend, why did she choose to lay down on me...keep in mind, this is probably the most romantic thing a girl can do for a guy...guys understand more than girls, but yeah
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I should mention, we got in a fight and her, myself and my friends, don't talk to her much anymore
Girls like putting their heads on guys shoulders or chest because of security, so why mine?
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