This is more of a "we" than an " I".
DP has always paid maintenance for DS (my DSS). They split when he was 1 and he's 18 now.
He finishes 6th form college in May and has a full time job for the summer (longer if he chooses not to go to Uni). DP has told his ex he will stop paying maintenance in May. She's hit the roof with no explanation as to what she expects!
For context DSS lives with us half the week and if he chooses uni then we will make separate financial arrangements directly with him.
We've always known that the maintenance doesn't get spent directly on DSS but supplements her lifestyle (it's quite a lot)
Advice please x