Hello:
Your situation is familiar to me because I attended a lot of Codependency meetings and groups where these patterns of behavior are discussed and examined.
At CODA, I learned how and why I was attracted to ON/OFF type individuals (there's a clinical term for this) and then HOW to deal with both my impulses to go for them and their impulses to be attracted to me. All I can offer in a little forum like this is a few hints about how I dealt with situations somewhat like yours and allow you or anyone to take it from here.
IMO, therapy and support groups was the way to go to BREAK my early childhood conditioning and programming to get caught up with an ON/OFF type of USERS. The best teaching I found was to build up and strengthen my Self Esteem and respect which made it nearly impossible to get caught up with an ON/OFF USER. It also helped to come to see how inadequate parenting had set me up to be so vulnerable to such a USER.
In the end fixing myself was the ultimate solution and, in Recovery groups, finding the solutions is the main thing.
Wishing you well,
Jim