From my husband:
Based on Igros Moshe EH 4:32: Rav Moshe’s maskana about men wearing rings ( ??? ????? ????? ??? ????? ?’ ??? ????? ?????? ??”?) could be taken as a mild discouragement of the practice. However, Rav Moshe writes this in the context of a polemic against double-ring ceremonies (which, IMHO, can only be done through highly questionable halachic sleight-of-hand). The chukos ha’goyim in having a men’s wedding ring is using the wedding ring as part of the ceremony, NOT in wearing the ring after the ceremony (ad meah v’esrim). Rav Moshe says that goyische men will wear wedding rings for ornamental reasons (“l’noi”), as well as (probably the most important reason) to make it clear to opportunistic women (r”l) that the man is married, and these are not assur mishom chukos ha’goyim. (I think one can find greater elaboration of Rav Moshe’s shita on chukos hagoyim from his teshuvos about Thanksgiving and Nittlenacht)
The only reason for a wedding ring to be assur is if it were somehow obvious that the ring was actually used as part of a double-ring ceremony as practiced by some goyische communities. However, Rav Moshe found it to be inconceivable that a double-ring ceremony would ever actually happen in the presence of a Mesader Kedushin, two kosher eidim and an audience including frum friends and family. More importantly, he found it inconceivable that a stam yid who sees a wedding ring on the hand of a chassan would believe that the ring was from a double-ring ceremony.
Perhaps a chassan who wants to be particularly careful about preventing perceptions that his wedding ring was part of a double-ring ceremony should wait a few days after the wedding before buying his ring so that friends at sheva berachos can tell that the chassan’s ring was not part of the ceremony. (my wife and I didn’t pick out my wedding ring until after our sheva berachos when we were already in Las Vegas).