No, you aren't wrong for getting bs something.   The only thing I would question is spending £200 on your SKIDs in the first place - very generous yes, but they have two bio parents to buy them clothes, you shouldn't have to reach into your own pocket. 

Your actions sound fair, caring, and thoughtful to me. I would steer clear of buying for skids, too. I am just learning this myself, and I can relate to your situation. I've bought many clothes and shoes for my step, and I do it out of love. At one point his BM mentioned that SS had no socks and asked if they were at our house. They were not. Shortly after this, when I went to pack SS's return bag home, I found like a dozen of my bio's socks in it. Huh? I'm guessing he took them because BM was asking him about socks. So, I went out and bought new socks for my SS to take back to BM's, even though it was not my responsibility. I've bought him many things which never come back to us. Not a huge deal, but when it is something more expensive like a coat, it is annoying and not thoughtful. Also, I make the least amount of money of any of the parents involved. I am definitely learning to set limits now. I don't want to, because I care, but when folks are not thoughtful in kind, it gets really old. I have decided I am okay with shopping for SS for my H's convenience, but only from his budget for him at this point. This may change at some point. I may just tell my H, you go spend your free time shopping for your child. The only other point I would bring up is in regards to your Dh's comment about spending inappropriately on a child with poor behaviors. I do agree with this line of thinking, but by your comments, it sounds like you were thoughtful and considered the current situation and were not out of line here. I think your DH is not being respectful of you, and both he and BM are taking advantage of your kindness and concern for their children. 

The only thing you were wrong about was buying clothes for someone else's children. Next time bm or the sds make an observation about clothes not fitting, direct them straight to your DH. They are his responsibility, not yours. Consider also that if you had done so, you wouldn't have felt the need to be fair and level things up thus avoiding your DH's snitty comment. Either way, you were rewarding him for helping you clean up after the skids were gone (how much mess do they leave and why are they allowed to do so?), not for his bad behaviour. 

The things that you mention buying are not really comparable to be put into an equation of fairness. I would give up on trying to be "fair". Instead do the following:

1. Your husband funds everything for his kids. He does the shopping for them and their needs.

2. You fund everything for your kids. You do the shopping for them.

3. If you want to get something for any of the kids you do so and do not worry about being "fair".

4. Repeat the phrase "ask your dad" if any of the step kids pester you for something. 

Life isn't fair and kids should learn that. Overall though things usually work out and just because you bought your son pokemon cards this week, doesn't mean that step child must also get a gift this week - but perhaps their dad or mum will get them a gift in a couple of weeks time. 

"Fair" is a very dangerous concept when it comes to different kids.  Regardless of if they are full sib BKs, StepSibs, or Half Sibs.

I am 6yrs the elder to my younger surviving brother.  I was always baffled by what I perceived to be the differences between how my parents raised me and how they were raising my younger brother including a perceived disparity I had for some big gifts.

My clarity came when they bought my younger brother a car at 16.  I got my first car when I was 19 and it was my HS graduation gift.  I moved home for a couple of years when I was 21 when I launched my company and needed to keep my costs low for a while.  

I made a comment to my dad about the car for my little brother.  He informed me that he understood why I might perceive a significant difference in how my brother was being supported and how I was supported when I was his age.  Then he asked... "Do you want to drive your brother and all of his friends around any time they want to go somewhere or do something because your mom and I have no intention of being his taxi drivers?"  That gave me clarity.  I immediatley helped my parents with finding my brother a car.

I agree completely with everyine above who said No, you aren't wrong. You most definately are not wrong.

Time to sit DH down and ask him if he wants you to back completely out of providing clothing for his prior failed family children and if he and BM want to deal with those types of things for their children and you will focus on providing those things for your own children?

Lather, rinse, repeat.

Find the right button to push to give DH clarity.  For me it was the prospect of being at my younger brother's beck and call for rides, etc... which would have severely interfered in my own social life and the time I could invest in my business.

To play devil's advocate: is it possible your DH perceives your son as badly behaved or overindulged, and the Pokémon cards weren't deserved? So not really about amount spent or fairness, then, in his mind.

You aren't wrong you already did more than you had to, so what you decided to buy your child is very much your business. 

the word 'fair' shouldnt be brought into this ,, this is how spoiled entiteled brats come about !!!!  My story regarding this,, when my son graduated highschool with honors , it was decided we would reward him with a new trail bike that both my DH and myself paid for as a special graduating gift.  my 17yr old never asks for anything and doesnt have a lot of valuable possesions as i raised him as a single mother and didnt have much money,, he values possesions and money with high value as hes never had a lot before and he cried his eyes out in happiness when we suprised him with it,,,,, little did i know that my DH had also purchased another bike to the same value and gifted it to the SS12 for absoluetly no reason and at the exact time as he claimed it would be extremley unfair to give my son one and not his son, WTF!!!!  It was a graduating gift for my son who worked hard and achieved honors,, it was his reward!!   If the SS graduates highschool years later with honors,,then he can be gifted one !  It completley took away from my boy's hard work and made him feel so sad and inferior all becasue of this so called 'fairness'!   Let your DH and BM buy the clothes for there own kids, save your money for your own children and you buy them whatever you want whenever you want !!!!! 

Maybe he was commenting on the fact that clothes are needs and pokemon cards are wants? If that is his reasoning this your BS is the only one that got something fun. 

But it's your money and your kid so you can spend it however you like. It's only a couple of bucks. I would absolutely stop buying significant things for stepkids and just tell them to ask their dad. Sometimes you cant get out of buying something without looking like you're excluding them or evil but I would set myself a dollar limit on stepkids spending. 

Fairness is highly subjective as many have pointed out.  What one child gets may be outweighed in appearance by what other children in the home get at any given time.  It can happen for a variety of reasons.. one child might get a new car at 16 because their parents can afford it.. but perhaps a much older child didn't because the parents were experiencing more financial difficulties at that time for them?  Sometimes "first kids" don't get as much because their parents are younger and have fewer resources ... but they get younger more active parents who theoretically can do more with them.  The late child may get more material indulgences but their parents may be older and more caught up in careers and have less quality time?  that's one way that things can be "unfair".

Ignoring the issue of stepkids for a minute.. when you are buying kids a general basic "need" like clothing (school.. or other necessary use clothes)... that is really not a thing that needs to be kept even all the time.. over time... generally it will become even as kids go through growth spurts at different times etc.. but in the near term? no.. just because kids needed a wardrobe refresh doesn't mean all your kid do.. and certainly doesn't mean you have to go buy the kids who don't need clothes or many clothes toys to "make up for it"

But, in this case, it sounds like you used your own money to buy his children some needed clothing.  Does he also buy your bio kids things?  do you find that level of spending to be equitable/fair?  I don't have a huge issue if you choose to spend money on his kids.  I used to spend money on my skids.. it's fine.. it's your choice.  But, your husband having an opinion on how you spend other money.. like on the cards... does he do that with your other spending? are your finances joint?  or do you keep them separate?

The simple response to your DH is not how you are "keeping it fair".. (which you don't need to do and probably shouldn't try).  The real response is that you bought him that treat because he has been extra helpful to you lately by helping you clean up the house after visitation of his kids.. and you got them for him as a thank you/reward.   That is the simple equation.. that he did something nice for you.. you rewarded it.... not that it was some larger issue of "fairness" in the home.