I'm a parent to an 18yo son and I'm struggling to cope with his traits

I'm a single mum who is struggling to cope with my 18yo son who has autism. I have been in a relationship with a man for the ls 11months. We are both struggling to cope with my sons strange ways, I've looked online for help and strategies but can't find anything. We are both so stressed out by his behaviours that we don't know where to turn. Please can anyone help u???

weve tried putting house rules and structure in place, but WE as parents don't know how to deal with our stress??

any help gratefully taken 

clare  xx