Fairness... Between children (Dp problem)

[Oggden1]

Dp has 3 dc. We have 1 joint.
He favouritises his eldest, his exw points this out regularly and I agree as does my family. He's completely blind to it and i have pointed it out but get in your opinion and no I don't.
He was a only child whereas I'm from a very big family, so maybe I just see it more? How do I get him to be fairer not only for my child but for his younger two as it will damage his relationship with them.
For example eldest wants to do x activity which Dp likes (this is issue as have. Alit in common) Dp has to go and finds money. Middle needs new school coat Dp says no money, I say don't do x activity them, answer I have to and its sonthing we always do.
Does expensive hobby once a month with eldest but nothing with little two. Eldest gets best computer etc etc.
Same for TV shows, activities etc. I put my foot down and told them we were not doing anything all the children couldn't do together last holiday which Dp sulked about but I MENT it and it was nice.
Maybe I'm being sensitive as we're blended but I was raised that as a parent if you have 4 kids and 100 quid for activities ecah child have 25 each to do so thing and that's that.
Or we do activity 1 child wants one holiday, 2nd child's next, 3rds one after and 4th last. So it's fair.
Is this a common theme?

How old are the kids?

Absolutely a needed new school coat should be a priority over a hobby (any hobby imo not just an expensive one) but maybe he thinks it’s the children’s mums responsibility to provide school clothes (I know my ex does!)

In what other ways does he favour the eldest? I’m thinking maybe he’s actually favouring himself and that happens to benefit the eldest because they both share this hobby / have lots in common?

They sharecists gor uniform eg shoes coats etc and we have our own small set of clothes for them here.
Yes favouring himself may be more accurate.. As it's stuff he enjoys

I’m not sure what you’re supposed to do about it, he may be a bit selfish, children’s NEEDS should always come before anyone’s WANTS (parent or sibling).

FWIW, I agree with your approach about doing one’s preference one time, another’s next etc and being as even as possible.
Favouritism can damage the relationships between siblings as well as between parent and child.

It's what I was brought up doing, I come form a bit family - literally 20 cousins. It was always strictly fair across the board about what people got or were expected to do.
I guess I can't do anything about it except keep highlighting that the younger ones have needs to and wants - which are important.
Ive suggested supporting the little ones hobbies. I pay for my toddlers swimming and baby dance lessons (hilarious but good for then) and Dp doesn't contribute. But he keeps saying no money if asked or I get cb for the toddler - which is true - but not strictly the point.

www.brparents.com/article/long-term-effects-of-parental-favoritism.html