“She sulks when she doesn't get her way”

What could be going on

Passive aggression: Fits if sulking replaces saying what she wants; check whether she denies being upset.

Uses guilt to get compliance: Check whether the sulking makes you feel guilty until you give in.

Psychological entitlement: Fits if she expects to get her way and treats your no as unfair.

Regression: Fits if she seems much younger when frustrated, and settles once comforted.

Emotional inhibition schema: She may never have learned to ask directly; check whether she struggles to state needs at all.

Silent treatment: Check whether sulking stretches into days of withdrawal used to pressure you.

Also said as

• he pouts until I give in
• my partner sulks for hours over small things
• why does my girlfriend act like a child when she's upset
• my wife sulks when I say no
• he gets in a mood when things don't go his way
• why does my partner pout when she doesn't get what she wants