Smilie, another technique that I have found useful. My STBXW has been in a 1 year+ R with OM. She started it whilst we were still living together. I tortured myself for many months with the question of "how could she move on so quickly after 14 years together".
How I see it now is, she wanted out, her meeting someone new was an inevitability. Why does it matter the timeframe? What timeframe would have been acceptable? 3 months, 6 months? It's just a number, therefore it doesn't matter. The time it takes them to move on is neither good or bad, it is only your perception that makes it so.
Me: 41 W:42 T: 14 M: 11 S: 6
"What happened happened, and couldn't have happened any other way...because it didn't"