Thank you all so much.
When I saw that this thread had grown to however many pages I though, 'gosh my life must be really, really bad'.
There is too much that H has said and or done for me to put everything, but none of it is positive. 
You have all helped so much. I can't even begin to tell you.
LAST NIGHT
H came home last night and ranted on so loudly that my ears were ringing by the end of it. That is absolutely, literally true. (to be fair I do have tinnitus a bit anyway).
He repeated that I was being selfish, that I could not mess about when children were involved, ruining innocent lives - same sort of thing as in his text.
He really made a big play of the whole children part and how people who have children have responsibilities which can't be messed with. He kept saying do you know what you've done.
He was shouting, banging the dressing table and blocking the doorway and looking v fierce.
He said he would have to get a restraining order and could I assure him that I wouldn't be making any more phone calls. That there was a woman terrified and crying because of what I had done. (there was a woman terrified and crying inside me because of what he had done, but only I care about her)
He explained at length about professional codes of conduct and the data protection act and said he would report me for breaking it.
OW and H were clearly v scared about how I had got hold of her number. He kept saying that even he didn't have it (but he has her mobile number for sure).
At first I thought OW had told her H but it transpired that was not the case.
I said that I had got the number out of the phone book.
Reading between the lines the two of them have worked themselves up into a right old paranoia about just how far my tentacles extend. (they are long)
H's very clear aim was to stop me contacting OW again. He was very keen to call in the authorities (as clearly I am running amok and creating public disorder).
He kept trying to bring it back to our marriage and trying to talk about problems there rather than what he has been up to.
On reflection the things he said seemed to have been quite thoroughly thought through in advance.