Hello everyone,
It has happened several times in my life: someone I really care for suddenly disappears one day and doesn't allow me to talk to them anymore. Sometimes I can tell that something is wrong, because they are distant for a period of time, other times it just comes out of the blue. If it were just one person or two, I'd think that something is wrong with them, but I've come to the conclusion that something in me must induce this behavior on other people. However, no matter how much I think about it or discuss it with my friends, I cannot find out what it might be. I have even tried asking these people, when I see that they become distant. I ask them why they are distant, if they are just busy or if something is wrong, but I never got any sensible answer, just excuses. It's not like I cannot get along well with people overall, though. I do have friends, and I've known some of them since we were 4 years old...
Some people have managed to get back to me though, and I've tried asking them the reason after this, but I cannot find a pattern that might lead me to a reasonable conclusion. One of them said I was too clingy, and since I heard this, I'm always trying my best not to be clingy. However, I've also heard answers ranging from "sorry, it's all my fault" to "you were the only one who treated me the way I wanted to be treated, I was a total idiot, wish I could go back in time". I don't hold any grudges, it's just that they're not too helpful there...
I recently met a guy online, almost coincidentally. I was looking for someone to practice a foreign language with, and I had met several people this way. However, one or two days after we first started talking, we fell in love. It's a long-distance relationship, so we didn't think it's going to work out, but I was happy, and so was he. I can tell that he was truly happy to talk to me and that he cared for me. A few days ago, he started studying for an upcoming exam. If I saw him online during this time (which didn't happen too often), I'd say hi, wish him luck in his study, and tell him that I miss him, and he'd answer some minutes (or hours) later, just for a small while. He was kind of distant indeed, but I figured I'd also be distant if I were studying for several hours straight. Today we spoke for a little while and he said he was tired, though he did seem happy to see me. I said "will we talk later then?", he answered "yes" and then "good night". And he just went ahead and deleted me from his instant messenger...
I've tried talking about it (not just this particular person) with my family and friends, and every single time it looks like the other person is out of their mind.

Can anyone give me a clue on what to look after and how to find out why I induce this behavior, or why I attract such people?