بسم الله الرحمن الرحيم
The origin of the wedding ring emanates from an old practice of the christians whereby the groom would place the ring on the left-hand thumb of the bride and say, “in the name of the father”, then he would move it across to the index finger and say, “in the name of the son”, then he woud move it across to the middle finger and say, “in the name of the holy ghost”, then finally the next movement would mean the ring then ended up upon the finger now known as the “ring finger” where the wedding ring would then remain and “amen” said upon it.
[Paraphrased Aadaab az-Zifaaf of Shaikh al-Albany p140 via Sahab, also mentioned by Sh ibn ul-Uhaymeen quoted from Sh al-Albany, (الضياء اللامع من الخطب الجوامع ج 2 / ص 446)
Shaikh bin Baz concerning wedding rings, “I do not know any basis for this act, this was not from the customs of the muslims…so I consider leaving it is better, it is safer and further from imitation of the disbelievers, it has not reached us that the Salaf as-Salih ever did anything of this nature”. [Paraphrased, http://www.binbaz.org.sa/mat/18573%5D
Shaikh Fawzan also stated, “It is not permissible to wear wedding rings at all due to:
1] Imitation of non-islamic customs
2] If the person thinks the ring aids in strengthening the love between the husband and wife then this is from Shirk”.
[Complete article available on Sahab http://www.sahab.net/forums/index.php?showtopic=129698%5D