What did Watson discover about the window Barrymore had looked out? What conclusion did he draw?

Watson discovered the window that Barrymore was looking out of had the best view of the moor. This caused Watson to conclude that Barrymore was looking for "something or somebody". Watson concluded he might possibly be having an affair.

The western window through which he had stared so intently has, I noticed, one peculiarity above all other windows in the house -- it commands the nearest outlook on to the moor. There is an opening between two trees which enables one from this point of view to look right down upon it, while from all the other windows it is only a distant glimpse which can be obtained. It follows, therefore, that Barrymore, since only this window would serve the purpose, must have been looking out for something or somebody upon the moor. The night was very dark, so that I can hardly imagine how he could have hoped to see anyone. It had struck me that it was possible that some love intrigue was on foot. That would have accounted for his stealthy movements and also for the uneasiness of his wife. The man is a striking-looking fellow, very well equipped to steal the heart of a country girl, so that this theory seemed to have something to support it. That opening of the door whlch I had heard after I had returned to my room might mean that he had gone out to keep some clandestine appointment.