Thanks again all, have had a bit of time now to read through all the replies
Just to note that outside of this issue (which is obviously a big one) we do have a good relationship. We laugh a lot, enjoy spending time with each other, he's very good with my DS, we both came to the relationship with some serious issues from our pasts which we have supported each other immensely with and I think we've both grown and been able to deal with these issues better with each other's support so it's really not all bad but this issue keeps reading it's ugly head.
Thank you @PlanDeRaccordement this is exactly the type of advice I was looking for. To be honest, it's been so long since I've had to share my space with someone I just wanted to know what is reasonable to expect and ask for before tackling this situation again.
@Notanotherfreak I think he's just been spending more time at mine due to lockdowns this year and last. He only met my son 1yr ago and prior to that we were both working, he was training the evenings etc so we really only saw each other 1 or 2 eves a week and mostly that would have been late in the evening I.e. after dinner so it wasn't an issue. I think I'm gonna have to pull back on the amount he's here. Tbh I've had to say to him a few times over the past year that I needed a few days to myself because I felt like I was never alone in my house. I'm a person who enjoys my own company so think I'm gonna suggest 1 or 2 nights max a week for now.
@WellIWasInTheNeighbourhoo thanks so much for sharing your situation. Yes, it's not ideal but I'm definitely going to take a leaf out of your book. Even though it's more of a pain for me to go to his I'm gonna start doing this. Maybe one night at his and one night at mine a week maximum. I'll make a point of saying I'm cold when I am and leave him to do the cooking, cleaning etc on those nights.
@Allispretty will definitely be having the conversation with him, because you're so right that it's rattling me and I will eventually explode. I have tried in a roundabout way to get him to see how huge my outgoings are but he's either oblivious or doesn't care... I'll soon find out. And you're also right in saying another man would just offer. I don't need looking after.... but it would be nice wouldn't it 
@SixesAndEights thank you, I did have this conversation with him but it was more of a general "I really think you should pitch in with food more, I feel taken for granted". This time it obviously needs to be more along the lines of "I'm feeling really effing pissed off now, you're taking the piss and if you want this relationship to continue then I need X, Y and Z to happen or I'm out".
Thanks again to everyone for taking the time to share advice and their own situations. As I said above, it's been a long time since I've had someone in my space so I don't know what's acceptable to expect and demand,. I don't expect him to pay any rent (and really don't want a live in boyfriend in the foreseeable future at all) , I don't even really expect a contribution to the bills, even a bloody acknowledgment when I told him how much it had cost me last year would be nice but the food is non negotiable now because it's just taking the piss. I'm gonna take a few days to myself, gather myself and my approach and have the conversation. I'll update when I can - Thanks again All x