I had a problem with several years ago with a guy whom I had doine many day walks with, even a few weekends.
Walked Offa's Dyke over 11 days. Fine at first until we were accompanied by another guy and his dog. The talk almost all day and in the pub in the evening was dog orriented. That accompanied by the fact that he was annoyed if the b&b only had a shower instead of a bath, preffered the double bed if there was one, and many lore annoying little attitudes.
Next walk (he had to give his wife at least 2 years notice) was WHW, can't be as bad as last time I thought. Wrong, he was really wierd. At one point when he'd delayed us chatting to another couple far too long and it being obvious they wanted to be on their own, but he oblivious to this, I carried on, on my own for a couple of mile. When he caught he announced that he din't need to talk to me during the day when there were other as he could talk to me anytime! With that i was going to part compant with him but the opportunity never really arrived. I did walk the last section to include Ben Nevis on my own (he thought that idea was ludicrous) and have to say that was by far the most relaxing and best day of the entire route!
We haven't walked together since.