I am not sure what kind of responses you are looking for.

I have found that sometimes I have the kind of chemistry with someone that leads to this sort of on/off relationship. The on/off pattern can be very addictive. When it's good, it's great and we forget how bad it feels when we aren't going through the great part.

In the long run, none of those relationships worked for me. I had to cut off all communication to finally end them, and it took me years to get over one of them, the person I thought would be the love of my life. It's very possible to have intense chemistry with someone you are not long-term relationship compatible with.