eandz
You are arent being oversensitive, and its not because you are from the US either! 
I am not really sure what to advise re: nursery. What is the key worker to child ratio there? I know from my experiences with ds1 that the start of nursery can trigger all sorts of viral and bacterial illnesses that N wont have resistance to (like CP, tonsiltiits, gastroenteritis, ear infections etc) Interestingly, ds1's excema got worse after starting nursery too - I put it down to them using paints/playdoh/sand etc which was proabably not that clean!!!
I would hate to think what a SW/HV would think of our medicine cupboard!!! 
It is chock full of stuff...for dh (asthmatic and has excema), me (got so many things wrong with me its almost funnny) ds1 (asthma, excema) and ds2 (excema) add to that pain relief for all of us, hayfever stuff for all of us, first aid kit, various eye drops, creams, ointments, anitseptics etc etc etc
So, I wouldnt worry too much about that..I am assuming that apart from the pain meds and first aid kit that the rest is prescribed??? If so, what are they worrying about? 
I think the other childs mothers attitude was not nice, but hey, we all have to deal with unpleasant people and IME other childrens parents can be a minefield I am quite sure I may have unintentionally offended/upset people in the past. I have certanly never done it intentionally. I know that I have been deeply offended/upset by the comments/attitudes of other parents wrt to ds1. I guess I have developed a thicker skin that you E as I really dont give a flying fuck anymore.....
You are doing the absolute best for your boy - you are getting him assessed and he is getting therapy. I do question why HCPs seem to think that nursery/pre school is so essential for SEN/SN kids....IME its not always beneficial at a young age and indeed can sometimes be harmful 
If N is that unhappy, maybe re think? Look at other providers of care?
Wrt the house and cleaning.....I do what I can. Dh helps when he can (not often) and we muddle along. It really helps sometimes to de clutter (freecycle/e bay stuff you dont want/no longer need) and try and get into a routine of certain tasks on certain days...so for example, if Ns dad can take him out to the park on a certain day, leave the jobs you cant do with N there until that day IYSWIM??
I wish I had an answer for you wrt the intimacy thing....sigh. Its something dh and I are struggling with atm tbh. I am just so drained - in every way - from dealing with ds1 and ds2 and the house and everything else that at the end of the day I just have nothing left. He has been understanding up to now (and he is pretty tired too tbh) but I do wonder how much longer we can go on like this....
Ds1's anxiety issues now mean that at bedtime we all have to get into our PJs (he has lots of sensory issues too) and dh has to sleep in his bed with him most of the night and ds2 always seems to end up in with me at some point during the night so its not exactly condusive to romance!
We are hoping that if ds1 gets a dx (we see the comm paeds on 23rd) that he will - al last! - get some help and it will decrease his anxietes and help his sleep...god what I would give for 4 hours uninterupted sleep!!!!!!
Its been a tough few months for us and the next few probably arent going to be much better but we do the best we can.
Be kind to yourself x