Hi OP
I think mine was somewhat of an unusual set of circumstances that won't probably apply to anyone else. I had a serious accident in the early stages of my pregnancy with my DS. It was touch & go. Thankfully we both pulled through, but I would never be able to carry another pregnancy. I was signed off work for three years to get me through the surgeries I needed plus rehabilitation time, then I went back to work x2 full days per week.
My (now ex) DH was becoming increasingly abusive. I knew I had to make a plan which meant running a home & providing for DS by myself. I could only make the plan work if I went back full time, which I did when DS was in year 2 (7/8 years old). My employer was fantastic and very flexible, I was still able to attend sports day, Christmas/Easter plays etc. Most importantly, I was able to provide DS with security.
He's an adult now. We were reminiscing over Christmas and I asked DS if he would have preferred me to stay working part-time as he grew up. It's funny how the mind works. In my head, I missed the normal day-to-day stuff with DS. In his opinion, I was always there for the times that mattered most to him. I always made sure that DS was the full focus of my attention at home, no distraction with checking work emails etc.
No-one wants to think of their relationship going wrong. My advice to anyone would be to make sure that you are in a position to support yourself and your children without any input from your OH/their father, which may mean increasing your hours. You also need to think about retirement/your pension.
IMVHO, it's the quality of the time you spend with your child/children is vastly more important than the quantity.
Good luck with your decision 