<human>: Can you succinctly summarize the text in 1-3 sentences?

So, I'm a little perplexed as to why ex boyfriends keep contacting me via Facebook. I've had 4 guys I used to date message me this year. And I should mention these aren't recent exes, these are relationships from at least 6 years ago or more because I've been in a happy relationship for the last five and a half years. 

Now the most recent message that I received was from somebody that I dated back in 2009. Mind you, we only dated for a couple of weeks but he was definitely "in love" with me or so he believed. I can surely say I never felt that strongly towards him which is part of why I broke up with him but, I digress. To the point. So he sent me a message this morning saying that he misses me and has missed me since the last time we talked which was about six years ago. Crazy long time to wait to tell someone you miss them right? Now, I know from the last time we talked on Facebook (2010ish) that he was married but it doesn't look like he's married anymore seeing as how all of the photos of he and his wife are no longer public and she's not on his friends list. 

So, what in the world possesses somebody to out of the blue contact you saying that they miss you when you haven't spoken in years? I'm not even close to the same person I was in 2009, and that's a good thing but does this person assume or hope I haven't changed? Something tells me that if I'm not thinking about my ex's and they are thinking about me that we definitely have nothing in common.

I should also mention that it came along with a friend request at 7:30 this morning. Now this is only like a week after a different ex from '08- '09 (who has a kid now) sent me a message at like 3:45 in the morning Just saying "hi I miss you". Weird.
<bot>: Anyway, I'm really not sure how to respond to this or if I should  even should respond to this. Any advice?