The vow says "until death do us part." We don't die in the Rapture, we just go someplace else for awhile, but we are very much alive.
No different than a Soldier Missing in Action (etc.). IIRC, the military generally waits seven years before it'll consider a petition from Next of Kin to have the MIA Soldier declared dead. Things "may" have changed since I was in, and varying circumstances may impact this.
If seven years is used as a standard to declare a missing person dead, then no remarriage until the end/after the Tribulation.
OTOH, there is case for abandonment since the Raptured spouse left the other behind with no intention of returning and resuming the marriage, in which case the person left behind is free to divorce and remarry. In some cases, there might be a year wait required by law/statute for either abandonment or separation.
Bet TPTB dream up paperwork with blanket, virtually automatic, approval to legally terminate such marriages to facilitate remarriage, property transfers, etc.
FWIW, my life insurance policy has a "disappearance" clause
Likely intended in case I become MIA, but I don't remember any exclusion for Rapture or alien abduction