Earnest,
Yknot is 100% correct. They can prevent them from getting married in the KH and even discourage any local elders from marrying them but from a WTS standpoint, the innocent mate refused to forgive and thus both the innocent mate and the cheating mate are "free" to remarry without congregational sanctions.
From personal experience, where this will come into play is if the man was the guilty mate and in the future they try to appoint him. I saw Bethel ask questions about someone who was a MS for several years and when recommended as an elder, a letter came back requesting the BOE to interview the ex-spouse (who wasn't a JW anymore) specifically to see if her former spouse's actions were why she wasn't a JW. I've also seen a situation where someone was recommended as a MS and had cheated on his spouse years earlier. She had forgiven him and stayed married but we still had to talk to her about it and ask if she "respected" him from a spiritual standpoint before moving forward. Needless to say, that was an uncomfortable conversation and caused her immense pain for having to relive the infidelity.
yknot -you know more about WTS procedure than the average JW elder. You're quite an elderette!!!