I was a sahm for 2 years with DS, and for 6 months of that DH was working away (we relocated after 6 months) and after that DH was travelling a lot with work.
I found it easier to cope when DH was actually working away as I had friends & family and a routine (nct group, swimming, etc etc) during the week.
It was when we moved to a new area and I was at home all day with DS and knew no-one at all, that I started to crack up.
We went to one toddler group a week, and sometimes when DH was away, I neitehr saw or spoke to anyone else (face to face) for 2-3 days ata time.
It was god awful.
We were also finding it hard financially so I decided to look for a p/t job.
I still sometimes have reservations about DS being in nursery (he goes every morning) but I love my job, have made some great friends, have a social life, feel so much more confident, and now am starting to make friends outside of work - as DS gets a bit older and is going to birthday parties, etc etc I'm getting to knwo some of his friends' parents.
I know this isn;t the answer for everyone, and not looking to open any debates here, but it has completely turned my life around.
I did also initially consider doing a few hours voluntary work a week, but we couldn;t afford childcare if it wasn;t being paid for by working, iyswim.
If you are going to be on your own all week you must insist you get some time to do otehr things at the weekends, imo.
How about booking up an adult education workshop on a saturday for something you are interested in? Or start going for a swim, or to a class of some sort, one evening?
You will get to know people really quickly if you go to a class.
It's totally unfair for your DH to monopolize what could be your free time.