I agree with most that this specific incident isn't the issue - it's his lack of emotional participation in the attempt to save your marriage.
From the outside looking in, it appears to me that he basically has realised he doesn't actually want a family - not to the extent of actually doing the work to have that. He's probably totally okay with the "idea" of parenting, so long as he doesn't have to do the shitty boring difficult bits, like actually engaging with a child, meeting their physical and emotional needs. He's all about turning up at school assemblies, looking proud. But the cleaning up sick, getting them organised every morning, changing nappies, comforting them - nah, he's waaaay too good for that.
If you split, he'll be Disney Dadding like crazy. Which is annoying, but at least you know the kids won't be actively neglected during their contact time.
The reason for his vagueness during counselling is because you're not actually doing anything "wrong" - he just doesn't want to be in the marriage any more. But he's too cowardly, and/or too concerned about his public image, to actually say that.
I think that's why the "fucking bitch" slipped out when his barriers were down. He thinks you're a bitch. Not because you ARE a bitch, but because you're doing inconvenient things like having emotional needs that you expect to be met by your husband, and for him to pull his weight parenting his children and keeping his house.
If it was me - I'd start using the counselling sessions to plan my exit and agree co-parenting strategies. I really couldn't be arsed dancing around trying to work out how to please a man who won't say what he actually wants.
Good luck OP 
(Oh and I'm another who doesn't mind this dirty talk during sex - but it has to be something both partners enjoy, and preferably have agreed beforehand. Suddenly springing it on you during sex, and especially in the context of trying to build more intimacy, is really not on at all.)