To expect stbxh to pay half of activities?

[Fairy13]

DS is nearly 2.
He has just started doing toddler gym which he loves, and I would like to start him doing swimming lessons, I think it is an important life skill and good for him to do activities.

I text stbxh 'hi, I'm thinking of starting DS with some swimming lessons, would you mind if we split the cost in half?' It's £140 per term. I cover gymnastics because it was only £3 a session and I didn't want the aggro.

He has just replied 'no, that's what I pay you maintenance for'!!!

He pays £120 per month for his child, nursery alone is £800 per month!

Maybe he is right as I suppose I could just not send him to swimming lessons... But I do feel resentful that just because he lives with me I always cover the lions share...

AIBU?

Have you pointed out the maths to him?

50% of childcare fees
50% of clothes per month
50% of food
Your rent/mortgage

It's ridiculous to think maintenance pays for everything.

Why on earth would a one year old need swimming lessons? Take him swimming yourself, it's just about enjoying being in the water at that age.

I have a friend in a similar situation - her ex wouldn't contribute to any extracurricular activities at all but was always on the sidelines cheering his boy and posting pics on Facebook about how sporty his kid was. Meanwhile my friend was paying subs, buying kid and shoes and managing the team! He wasn't going to be a good dad, it was a control thing. Hmmmm, what's my point. Sounds like he's in battle mode.