I think his life took a turn in a direction that he wasn't expecting when his wife died so suddenly.
I very much doubt he would have divulged so much about his personal dalliances and slightly unusual spiritual interests had his wife still been here. He'd have just been Mr Reliable Ken Barlow for the rest of his days. I think her loss must have plunged him into a bit of a crisis.
Yes, that's the first thing that comes to my mind- the timing of his new 'playboy' persona does seem to coincide with the loss of his lovely wife. Poor guy.