How to deal with an infatuated person?

[LTC]

I like using twitter and making friends, this past month I met this guy. He started being so sweet and charming and felt he liked me a lot. I told him I'm married but like to make friends in twitter and I just wanted to know I have no other interest than friendship. One week later he said "I love you! I like everything about you and I just know you're the one for me!" I once again told him I'm not looking for nothing more than friendship but he just won't give up. As soon as he sees me in twitter he'll start sending me tweets, and I feel terrible because he's a good person but I don't see how he could feel this way about someone who he does not truly know. I've told him, we shouldn't talk anymore and he just went nuts. What scared me is that today he told me I should just come and live with him and leave my husband. I'm scared what will happen to this guy if I just cut him off, but at the same time I feel I'm being manipulated into something I said no from the beginning. I'm truly worried about him, he's really sweet and feel he's just lonely. I've told him he should meet more girls, talk to the ones he's following, but he won't talk to anyone but me and even told me all tweets are dedicated to me. Please how would you deal with this? I"ll do whatever I need to do to stop this. I'm just scared for him =(