My once-closest friend and I have seriously drifted apart. It's come as far as that I do not want to invest any more energy in the friendship and I'd prefer it to just quietly end.

I am unsure, however, whether to tell him (live, or by e-mail) that I consider our friendship done. A complicating factor is that we are both part of an extended social circle centered around our bridge club, with many mutual friends. I do not expect him to retreat from that circle anytime soon, nor am I planning to.

A bit of background may be in order. We have been friends since college, and over the last few years have mainly bonded over board games and bridge. We are both around 40, and are both male.

I'll try to name a few reasons I want to end this, but I'll try and stay short:

 - He complains a lot, always about the same things--mainly work and other people in his life. He takes advice about the issues, doesn't follow any of it and then complains again next time we meet. Rinse and repeat.
 - He has incredibly high expectations of people he interacts with in matters of communication, how they should behave and what they should do for him. And doesn't live up to them in return himself.
 - Connecting to previous: if I, in his eyes, failed his expectations, we have to *talk about it for a bit* and then he puts me on the defensive about what his slights are or, even, as he puts it, 'the standard of people you interact with'.

Lately, we have had very little interaction. After I had to find out about his girlfriend's pregnancy through her social media rather than him telling me, I decided not to put any effort in this anymore. A few weeks ago, he (too late, imho) proposed to have dinner together again, with his partner and mine. I avoided that proposal and have not had contact since.

If I prefer this to die a quiet death, is it better I end things with him by an email or a talk? Or is it better to just stay quiet and hope that he takes the cues? I'd prefer to keep a respectful distance while still interact every now and then, because we are in the same club.

*tl;dr*: My old friend has worn out my patience, partially by not initiating much contact. We are going to be seeing each other in social situations, but I want our friendship to be over, preferably quietly. Is it best to 'officially' end things with an email or a talk, or not?