I have been a sahm for nearly 8 years! DSs are now 9 and 6.
Clearly mine are both in school so I get a lot of comments on why I don't work
Dh earns enough to support us; because I am a sahm and enable his flexibility in his work.
Pros, instead of stuck in an office you are playing with sand/playdoh/gardening/at the park etc
People complain about their work day, you think, hey I made lego cars today 
Life moves at a slower pace
You are there to pick your child up from school not having battled your way out of work and through traffic
No stress of juggling childcare
My health has improved considerably now I don't have the stress of working and childcare
Cons your children do not appreciate it and ask why they can't go to after school club
Your children assume they too will have a "wife" who will cook/clean/shop
You can be taken advantage of by other parents who work (never happened to me, but my friend is a constant on call babysitter/child collector for so called friends)
People treat you with contempt, like your decision is a slur on the choices of working parents, not so, each to their own, and I didn't plan to be a sahm, I worked part-time.
It can be lonely, but being alone is not always lonely. I learnt to enjoy being alone.
Good luck. It was the best thing I ever did.