How does one deal with impulse?

I am impulsive. I do what my heart says. Though I have calmed down quite a lot, I still expect too much too fast and sometimes I give up too fast on one thing and want to move on to the next thing. I fire up, I get bored, I think about billions of things, to the point where im tired and I dont want to think at all. This happens quite often in my relationships. I guess I have a lot of energy to spend. Who has this and who can explain this? What do you suggest one does?