The Shaykh here quotes from Shaykh Al-Albani: The origin of the ring worn by the two spouses.

The Shaykh : Shaykh Al-Albani (may Allah grant him understanding) mentioned that the origin of this ring is taken from the Christians, and that the priest among them has the groom come to him and place this ring, I think, on his ring finger, then his index finger, then his middle finger, and say, "In the name of the Father, the Son, and the Holy Spirit," and the like. Thus, it also involves adopting the customs of the Christians and what they are upon. If it were a mere ring, we would not say anything about it, but if it is accompanied by a belief or is a following of the customs of non-Muslims, then what a person should do is avoid it.