Attachment with people

A year and a half ago, I met a guy on the Internet. There were common interests in almost everything. 5 months was very good and bright communication. But then I had a difficult period in my life, I just psychologically could not communicate so "deeply" with someone, because I was constantly in my own world. Therefore, the communication ended, I regretted for a while, but then somehow forgot. 9 months passed and suddenly she felt sad and decided to explain the past (then she did not explain the reason to him). Communication began again, but more intensely. Then we passionately communicate with him all day, the next, a couple of three messages and that's it. I know that there are other girls with whom he corresponds. And I'm pretty jealous about it, so that makes things even more complicated. I should probably say that there is no particular sympathy here. Yes, I like it, maybe even as a guy, but without continuing. And so always in life I become attached to even the most unfamiliar people. When they are kind to me and interested in me as a person, that's all, I lose my head, I trust, and I'm a melancholic and it really means a lot to me. Maybe there are some leading questions that will help me solve this problem? I will be very grateful.