Is love a cruel punishment?

Why does it always feel like a punishment when I allow my heart to feel? Isn't it supposed to be like all the poets describe - Filling up the soul, walking on air? Instead, I feel trapped behind higher walls with each retreat to safety. I don't want my heart to become bitter, but I all too clearly understand why people do.

I just want to know what horrible thing I did, which got me sentenced to an unknown level of Dante's inferno saved especially for the lovelorn.