tell me how can you chase happiness if you don't have the heart to be hurt?

I went through some old journals of mine and came accross things I wrote which were inspired by someone I was with at the time. It was such an unhealthy experience for me emotionally and physically and now when I read it all it hits me how even when you are aware of things you do wrong you still do them...Is it because we crave trouble and this type of painful excitment? I'm still trying to figure it out....Those feelings are behind me now, one learns from it.