I'm not sure there can be loving without commitment, although commitment takes all kinds of forms, and there can be commitment for the moment as well as commitment for all time. The kind that is essential for loving marriages - and love affairs, as well - is a commitment to preserving the essential quality of your partner's soul, adding to them as a person rather than taking away.
We marry to grow up, to escape our parents and to inherit our share of the world, not knowing who we are and who we will become, so it is left to marriage to make it clear which ones of us are growing in the same directions and which are ships meant to have passed in the night.
Marriage is supposed to do everything, like Duz, which is more than half its problem. It is said to save us, define us, give us purpose, keep us from loneliness, and incidentally balance our diet and wash our socks, and when it doesn't, we get divorced.