OP I'm so annoyed on your behalf.
You said, he is a totally relaxed person and the last person who would be described as (gaslighting and controlling) by anyone who knows him.
Gaslighting: Psychological manipulation of a person usually over an extended period of time that causes the victim to question the validity of their own thoughts
Here's some things he's said to you:
He says I’m destroying the marriage by being like this
We have had the emotional affair conversation and he refuses to believe such a thing exists
I’ve spent the last few months being told I’m paranoid and controlling
He says I’m basically destroying our young family and marriage because he has a friend who happens to be a woman
It was his suggestion I start the ADs
A week ago I asked him to make an excuse to her about not replying to her texts and he refused as it would be embarrassing for her and upset her
(He's) saying I’m being erratic and off my head and he won’t be told who he can be mates with.
He thinks I’m just depressed and menopausal so this is why I’m like this.
You are having a completely normal reaction to a friendship that seems inappropriate. He should be bending over backwards to make you feel loved and secure but he's not. In fact, he's only concerned about upsetting her.
He's gaslighting you to make you think you're off your head and it's you that's controlling. It's all your fault because you're paranoid, depressed and menopausal. Classic gaslighting.
I'm so sorry OP, none of this is your fault and you deserve so much better.