Thanks for all the replies, really helpful. xx
@Nuttyfellalovesnutella 'Maybe it’s him who needs to see a therapist if he needs to keep hassling you.'
@MimiLaRue 'Would you tell a gay man he needs therapy because he doesnt want to have sex with a woman?'
Good points both.
@Jeleste ''oh well maybe you should try therapy, so you learn to like it. Youre really missing out!''
Lol!
@Shoxfordian 'There's a word for a man who tries to coerce you into sex and it's not therapist.'

To those who suggested it was anal: -it's not usually anal :) Though he did go 'gah, I really want to...' the other day in the bedroom. Usually he's not asking for these things in the heat of the moment.
It can be quite a range of stuff, some of it quite extreme, but the 'you could have therapy' one (he's suggested that a couple of times) was that I don't mind giving oral sex but I don't like receiving it, it just makes me jumpy.
The relatively extreme thing (by conventional standards) is adult cinemas, where he used to like watching me have sex with other men. So often when we meet up he'd be like 'I don't suppose you'd like to go to the cinema today?' edited by MNHQ*
And he likes 'pegging' and is bi, so those examples are great but unfortunately wouldn't work. Maybe I could suggest he gets therapy to like the idea of 'urethral sounding.' www.lovehoney.co.uk/bondage/cock-ball-toys/urethral-sounds/ Not that I want to do that but I could keep bringing it up to him in response, as I don't think most guys like the idea.
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As to whether he attempts to control me in other ways- my best friend is my ex partner. FWB doesn't want my ex knowing that we still have a sexual relationship, so I'm 'banned' from talking to my bestie about the sex, otherwise FWB has said he'll cut ties with me. He doesn't particularly mind me talking about it to any of my friends who don't know him though.
I had a lot of therapy about him in the past, mainly for different issues, although one therapist did tell me to tell him I don't like the cinema and to stop doing it, and I did.
You are all right- if he mentions any of it again I'll just ask him to stop doing it, as it's manipulative.