Study your current relationship
You're going to hear me say to look at your existing relationship before you move on to another. Look at yourself and try to decide what is wrong or right about the existing relationship. Do this BEFORE you get into a new relationship. If you don't, you are likely to either a) hastily leave the true love of your life and regret it later or b) repeat the same relationship mistakes over and over.
Old relationship versus new relationship
For most of us, an old relationship lacks the excitement and the unbridled lust of a new relationship. I think some people are addicted to that new relationship feeling so they go looking for new love all of the time. But old relationships have a deeper and equally beautiful feeling to them as well - friendship, true intimacy, (and yes, sometimes lust, as well). This doesn't mean you have to stick with the old relationship -- get out of an unhealthy relationship. I'm just saying that all new relationships eventually turn into old ones.