Thanks so much for your replies.
This is my set up in a nutshell:
I am single parent to DS aged 11, I have a nice comfortable home and earn a good wage. I don't necessarily struggle financially but am definitely not flush either.
Have been with DP 2.5yrs, he lives rent free in a house his parents own. He earns less than I do and is currently furloughed. I do spend maybe a night every 2months at his, maybe less given the year that was 2020. I also think my house is far more comfortable, is warmer (he has open fire but rarely will turn on heating) and always stocked up. It's also much easier for him to come here than for me to pack make up, work stuff, clothes, sort out the animals so they are okay while I'm away etc. We live 15min drive apart.
There has been a couple of instances the last few days that I've kind of snapped at - lights, heaters, electric blankets left on. When I've pointed this out he hasn't seen it as a big deal so I snapped and said "It's all very well when you're not the one paying the bills".
Cooked a lovely Sunday roast recently and he had not even finished his plate when he said "Did you get snacks and nibbles for later?" 
He took an item of food out of the fridge and had a piece in his hand and I asked him not to eat it as I have a strict meal plan in place every week to make my shopping delivery last and he threw it in his mouth with a smile.
Had to tot up my electric/heating and broadband bills for 2020 for my tax return this week and when I told him I was shocked that it was c.£2,500 he barely batted an eye. He doesn't seem to understand the enormity of my outgoings, my monthly bills exceed what he earns in a month.
There are evenings when he will just snack and finish things in the fridge cupboard and it just bugs me because I've already given him dinner and he knows I am keeping a strict meal plan.
Knew I had run out of milk and eggs yesterday (mostly consumed by him) and even though he was out of the house yesterday didn't consider stopping at the shop to pick some up as a thoughtful gesture.
He does occasionally bring the odd meal/takeaway but it's not consistent at all. He will tidy up a bit, empty dishwasher but nothing that makes any huge dent in my housework to be honest.
My DS is with me 50% of the time and to be honest, I would just throw on a jumper and a pair of woolly socks when I'm on my own 😂 but when DP is here I like to keep the house nice and warm so heating is always on when we're together.
I don't know what I expect from him really, I just wanted to see what other couples do in similar situations so thanks for the replies so far