I have come to understand over the years (from what I've been told), that the initial stages of what we understand love to be is actually infatuation. That butterflies in the stomach, giddy feeling is no less important to the big picture of full-on love because it's the result of all of those hormones and chemicals in the body firing and causing you to be attracted and bonded to another person...which is what makes it really hard to let go of that person when things end.

After the infatuation fades, because that giddy feeling doesn't last as full-on forever, love is a commitment and a choice: I'm with you, you're with me forever. I choose to love you and to cherish you and to be with you and all the other stuff.

I think if there are doubts, that complicates the path from infatuation to "I choose to commit to you, full-on, come what may." And maybe it's right and healthy to decide not to go further. The pain comes because you've invested time, energy, and feelings into another person, and have bonded with them. All of that stuff I said about infatuation, your body and brain responds to them and bonds you to the idea that, yeah, this person is going to be around. It takes some getting used to when that is no longer the case. And I'm sorry it hurts; I totally understand. I'm going through it, too. There is no magic switch except time and distance. But it will feel better, eventually.