Hi Surviving
This is triangulation, the ex is a third party … Your partner may feed off the attention and fuss this is causing. Ignore his ex, your boundaries that you and your partner agree on are what counts as if he then crosses those boundries deal with that with him ,not her. If he is breaking your boundaries he has no respect for them , if he cares be would at least discuss with you – without her involved – to understand why it upsets you. If he often does things that upset you and doesn’t give any consideration to your feelings that is a red flag.