Turning things around. Like if you suggest he loses weight, he tells you you are the one with the problem.
Starting to accuse you of being unfaithful for a spurious reason, like a man rang you months ago and this means you are shagging this guy.
Making reasons for keeping you away from certain friends or family members. His or yours.
The psycho ex. This is so that should you ever meet her you will not listen to what she says. It could be that she was emotionally or physically abused by him, or that he was a cheat.
Unusual similarities between the exes.
Strange phone behaviour. No reply when you phone or no reception, changes in amount of calls and texts.
The hobby. New hobby that involves weekends or overnight stays away. Usually male-only events to places with poor mobile reception. probably a hotel bedroom not a cycling event in the Peak District
Changes in attentiveness.
He's nipping out on a quick errand but he showers, shaves and dresses smartly just to nip to B&Q or Halfords or something, and he comes back hours later without whatever he went out for.
Suggesting that you have MH issues, when you don't.
He blames your hormones. PMT, Pregnancy, Perimenopause, Menopause for anything.
Spending a lot of time down the pub but in a different one to your local, with a mate of his you've not met. Darren will turn out to be Karen.