I found the OBS today. I sent him a message and we chatted for a few minutes.

Apparently the affair started in August, not October. Also, the OW was still "working" on her relationship with OBS until this week when he finally kicked her out.

OBS had no idea I existed. He was also told they just "hung out" in the hotel back in October. No mention of the kissing.

It feels like a weight has been lifted to get the other side of the story. The truth will set you free.