Apologies, I misread your question and thought you were referring to one on one with children.
i certainly found it difficult after number 3, 3 DCs under 6. For varying reasons I struggled, so did DH. We just cut down on certain activities, changed situations to suit. Namely we invested money in improving our outdoor space so they had plenty of fun stuff to occupy them at home.
Every child, couple is different, some parents can handle anything, others need more of a balance. Two I was perfectly fine with, I was told 3 just slots in and is easier, yep not totally untrue, but then they develop personalities…
Mine are 7, 10 & 12, I had all day with my 7yo who was apparently too ill for school this morning but ok to jump on a snowy trampoline for 2 hours with the dog this afternoon. I picked 10 & 12yo up and decided to go shopping and have tea at Asda, they love the pizza but the ovens weren’t working so they begged for McDonalds but insisted seeing we were already at Asda could they go to homebargins, matalan etc.. I got home and my brain was frazzled, I’d spent less than 3 hours with all 3 at once.