Relationships. Never rush into things.
But then, if you really think you wanna be with that person, chase him/her. Don't wait. Chase until you tie the knot. That there's no room for someone else to take his/her breathe away like how you do.
If you think you have fallen out of love on a person, leave. If you have fallen for someone else, leave the current one. Take your time. Think. Give your heart some time. Don't break your heart because of your own stupid decision.