My DH does this. When we bicker and row (which we do a lot) he says, 'You criticise me but there is so much I could say about you that I just don't.'
When I challenge him to be honest, to say what he means and to let me either defend myself from the accusations or modify my behaviour, he refuses to say anything.
My reply is that if he will not be upfront with what dissatisfies him then that is his problem to deal with, not mine. Apart from anything else there is always a strong chance that, in such a case, that he is making it up. 'I know what I know but I am not telling you,' is vague nonsense.
In my husband's case, he will not come out with that which annoys him because he knows I am clever and rational and that he will not make any criticism stick. Of course, were I in the wrong, I'd apologise and he knows it. In a way, his vague accusations are a kind of sulk where he is trying to gain the higher moral ground but without any evidence or right to hold it.
It sounds, OP, that you are in a quandrary. You are a nice person and you are being taken advantage of by a bullying other. You will either have to grow an armadillo shell against your DH (and DD) or give some ultimatums about the behaviour of those with whom you live along the lines of, 'Put up or shut up.'