I am afraid that, that old chestnut is probably the oldest one in book of recipes for disaster. The 'my wife does not understand me' line, or the 'I am only staying for the kids, because we never have sex' are more baloney, and purely a randy ruse to slip into your stockings for some egg snog and Christmas nookie.
Forget facing the rejection, 'to clear the air' is merely an excuse for setting up a further randy rendezvous, where he plans to read you his manifesto for messing you about for the foreseeable future. With men like this, 'facing the rejection' comes way further down the line, probably once you have spent several Christmas's and birthday's alone because the wife he is apparently leaving has just 'forced' him to move house, go on holiday, go to sports day etc etc.
The term 'be careful what you wish for' comes to mind, because to any young woman with half a brain, a man like this ought to be as appealing as a kangaroo's anus in a bush tucker trial. 'Do as you would be done by' is another common one, and what you need to be thinking is would you like to be done by a guy who can do this to his wife??
My advice to you is that you safeguard your reputation in the work place, by firstly resetting your professional boundaries, and secondly do not engage further with this cliché on a romantic or social level.
This man is about as useful to you as a photocopied bottom. Leave this experience under the mistletoe where it belongs, and look for someone who is built of better moral fibre and who knows how to behave in and out of work.
Laura's recipe for Sorbet Swizz (the ultimate boozy cheat)
500ml good quality lemon sorbet
50g fresh basil leaves
A generous splash of Martini Bianco or Vodka
Sneak away from the table and remove sorbet from freezer about 10 minutes before serving. When ready to serve tip sorbet into a tall container, add basil and Martini splash and blitz with a hand blender for a second or two. Spoon into glasses and serve with a wafer, biscuit or wand on the side. Take care not to blitz too much as this will make it runny rather than the whippy consistency in the picture.