I get this with my H, too. All sorts of little signs that he's not coming from his rented room when he calls to say he's coming over at odd hours of the night or morning.
I used to try to 'do the math', as it were, as to how long it should have taken him to get from point A to point B, but then I realised that I was just doing my own head in.
I keep repeating that any OW is a symptom of his illness, nothing more. It's almost impossibly hard, but... ya gotta do what ya gotta do in these cases.
And yeah, the timeframe is hard to take. In my case, around 16 months, I guess - if the DB estimates are on track (i.e. after 16 years of M). That means another 10 months, at least, before I could hope to see any impact from my DBing efforts.