I indeed feel like a connection junkie who was scavenging the same source as she was and we happened to find it in each other for a while.
I "get that". It was described to me as being a person "needing to be in a relationship". That was actually me. The emptiness to which you speak is something we often hope/expect can be filled by "someone", via a relationship. Sadly no one person can "fix" that which is broken inside of us. So what often happens is two "unfulfilled/broken" people meet, only to realize the issues we had are still there.
A wise person said "relationships are about two emotionally healthy people coming together, with the sum being more". In other words, neither of you relies on the other to "fix" unhealthy aspects of each. It was our individual responsibility to address these before hand.
I spent several years "fixing me", only to come away realizing I really don't "need" a relationship. I actually live alone now (not that I am suggesting that for anyone else), but making peace with our "internal demons" can result in a change in how we see life and relationships in general.
It seems counseling may be something to which you might want to consider. It really helped me. It will also help you better understand why your relationships seem to follow a predictable "loop"; why you maybe find yourself making the same mistakes. The reasons are often very deep and require professional help. With professional help I figured out mine. It changed me.
All the best