I wouldn't tell her I was hurt, I'd go along the lines of "It was a lovely thought of yours to give money to DH to spend just on himself. He does have this problem of feeling guilty / not thinking of himself / wanting to spend on me/the house, etc" You don't need to say that you feel betrayed or anything like that as she will (hopefully) feel a bit awkward and embarrassed anyway that your DH obviously told her and that you have no secrets from each other.
You could add what he's thought of spending the money on, or, if he's already spent it, that if you'd known she was going to do it, you could have added a bit more to it as there's for example, this fishing rod or jacket which he really wanted.
Personally, I'd give her the benefit of the doubt that she didn't mean any harm and I wouldn't let on to her that I feel bad about her doing it.... But neither would I forget it! (I'm a Scorpio!)
Good Morning Saturday 25th April 2026
HMRC slightly angry is an understatement



