She can dress for herself and still know exactly who will see it. Those two things are not enemies.

The signal is usually one notch, not a whole costume change. A dress a little sharper than the place calls for. Perfume that stays in the doorway after she passes. Lipstick picked like there might be photos later. The jacket comes off once she is seated. The earrings show every time she turns her head.

None of it has to announce itself. The gamble is whether he notices the extra care and treats it like it was put there on purpose.