chillyogawine I am sorry you are going through a divorce and your brother is having problems.
I think not enjoying or not wanting sex is probably far more common than any of us realise. What is intersting/sad is that your SIL is willing to be so blunt about it and make it so clear. Either she is very sure your DB will not leave, or she secretly hopes he will (which doesn't seem right when you say she is quite jealous).
I don't understand this "...she tries it on coz she's drunk and feeling up for it he feels shit again as he is being used to fuifill her need and she might as well get a dildo in that case!" So sheis up for sex and he feels that she is somehow using him? That doesn't make sense to me. Presumably if she wanted a dildo she could buy one and use it privately and so the fact she does want to have sex seems a good thing.
Or does he suspect she is faking it because she is drunk.
"I will suggest he goes to counselling just for himself so he can work out what he wants" Good idea.
I agree with StrawberryJelly these are important questions...
"When did the loss of intimacy begin?
After children? If so, maybe there's issues around birth trauma or maybe she has lost her confidence?
Or perhaps she doesn't feel the passion for her man anymore? They should try and spend time together like a date night every so often to try and rekindle any kind of spark but a deep level of intimacy require communication and understanding. It must be hard for your brother not understanding why this is happening."
LwejiI am not sure what you mean, "It is odd that he's happy to have sex with her when she's drunk, but I realise that she hadn't told him before. Still, it doesn't sound like he respects her wishes in that area. He needs to back off." But wasn't the OP just saying he doesn't want to have sex with her when she is drunk?
I think one problem' is that women are reaslising they don't have to have sex, and because some of us are not that interested in it, that means men are not getting it so often.
OP if your SIL were open to the of an open marriage would your DB want that?
The thing is he is totally smitten with her so it is sad he will probably stay in the life that is making him unhappy.