I watched a program offering the hypothesis that wedding ring derive from a 'barbaric' time in human history. While man was still a nomadic creation they would steal women for mates and bind them for a period of time so they could not run away. Eventually they did not tie them up but tied a piece about their finger, just to remind them that they should not try to run away.
Interesting... I think they would tied a piece about a wrist (like a bracelet) rather than a finger. Necklace could be used as well. Indian women (as from India) would wear a black bead necklace instead of a wedding ring. A former co-worker told me that black beads are a must in the necklace and some silver/gold beads can be included. An ornament can be included as well. I like the co-worker's golden filigree ornament on her mostly black beads with few gold beads necklace. If you see an Indian woman in a sari, look for her necklace.