Have been a SAHM since having DD coming up to 5 years ago. Now also have DS 10 months.
For me my reasons were fiesta bd foremost that I wanted to stay at home with her. I didn’t want her to go to childcare and we don’t live near family or would want them looking after her anyway (NC with abusive PIL and my parents can be very difficult).
DH works long hours with lots of last minute unpredictable overseas travel so it would have fallen to me to cover all drops offs and pick ups, sickness, holidays etc and after watching friends struggle with this it just never seemed worth the headache!
Plus DD wasn’t easy to conceive so after that particular battle I just felt at the time that nothing was more important to me than being with my baby.
Also, DH earns enough that I don’t need to work financially. And he couldn’t do his job and have a family without me at home tbh - he works 60-70+ hour weeks +travel
Up until recently I loved staying at home. But since DS has come along I’ve struggled with some PND. Juggling the two of them and their different needs as been really hard as I have no family support and DH is largely absent and we’ve moved (again!) to a new area so I’m slowly making friends but no one I would feel close enough to to ask a favour of really.
Some days I feel so touched out and joyless. But thats largely down to DDs emotional needs and DS being a refluxy, colicky, fussy, velcro baby, poor sleeper etc
Some times I think back so wistfully to my child free days and how easy it was just to pop to the shops(!) let alone long leisurely lunches, lie ins and long haul travel
But that’s nothing to do with SAH v WOH that’s just having kids full stop! 
Anyway, at the moment no I wouldn’t change things and am glad I’ve had this time with the kids. In the future when both at school I will consider my options re: employment or voluntary work