well tbh rosa that argument has backfired on me before.
her dd never told her mum she had a boyfriend
DD and I knew for months and I never saifd anything
I even started a thread about it.
I never said a thing,thinking I would be betraying X's confidence.
Then her mum (my best friend ) got a call fomr boyfriends mum asking about sleeping arrangements.Cue: my best mate being seriously embarassed as she said her dd had no bf.
Anywya she found out I had known and was a bit peeved I had not said anything.