He then pointed out that I always say that i am assuming in working on things that he was going to be on his best behaviour going forwards, so if I was holding back on the basis of what he was capable of (based on past experience) then I wasn't giving him a fair chance to prove he can change. Fair point I think?!
Not really. I think you are both discussing a lot about the Hypothetical Future World, which isn't particularly helpful. In the Hypothetical Future World, you have a cast iron guarantee that he will never ever behave abusively again. Therefore you should trust him and love him now, like you would in the Hypothetical Future World.
The problem is that he's shown in the last 2 months that cast iron guarantee is worthless, and whenever he is stressed/angry about your affair/ he reverts to type. So you have zero evidence the Hypothetical Future World has any potential to exist. And therefore this entire argument is pointless. Why do you "always say that you are assuming in working on things that he was going to be on his best behaviour going forwards" when that patently isn't true? Are you still saying that? I'd say it's totally fair for you to think that his recent behaviour is evidence you can't possibly assume that at all, and therefore need to act accordingly.
He's sent me loads of articles about how to fall in love with your husband again
I'm sure he has. What about what you actually need, and are actually asking for? Time away, sitting on a bloody bench, space? Is he listening to any of that? Or does he just believe he can argue you into loving him?
You're back in the judgement court again OP, desperately trying to sort right from wrong, weighing up arguments and logic against each other, which is a futile exercise because you can't argue with feelings and you can't rationalise yourself into loving someone, especially when they've behaved as he has.
Are you still seeing your friend this weekend?