This is an interesting question that was recently posted on the divorcedcatholic.org forum. There are many different perspectives, that’s for sure. Here’s mine:
Having recently gotten married (2 years ago) I remember very well the words I said to my wife (and she to me): “Monica, take this ring as the sign of my love and fidelity.” A wedding ring is a Sacramental. It is a symbol of a Sacrament–the Sacrament of Marriage. As far I understand, having a ring is not a requirement of the Sacrament. It is simply a visible symbol that the Sacrament took place. (Whether it is valid or not is up to the Tribunal should an annulment be filed, but that is another topic.) In the eyes of the Church, you are married whether you wear a ring or not. The ring is given by your spouse as his/her sign of their love and fidelity. So, using that logic, if they are no longer demonstrating their love and fidelity, they have reneged on the promise that the ring symbolizes. A personal decision would have to be made by the ring wearer of when their spouse reneged and if it is permanent. If they believe the promise is no longer being honored, it would not be inappropriate to take the ring off. Certainly, after a civil divorce would be a clear indication that the spouse is no longer standing behind the promise that the ring conveys. However, it could be very clear earlier then the official divorce date that the spouse has abandoned their promise. It is very important to understand (as I think most Catholics do) that just because one is not wearing a ring, does not mean they are no longer married. Ring or no ring, they are required to honor that marriage.
I also want to add that it is quite possible for a spouse to recommit to the marriage before, during or after a divorce. When this happens it is perfectly appropriate to put the ring back on. After all, it is a sign of an existing reality. I personally know of a couple that was legally divorced for 3-4 years and then reconciled and renewed their vows and started to wear their rings again.
I took my ring off when my divorce proceedings started.