My mum said upfront that she will not help look after my kids. She doesn’t have any patience either. So my husband and I made the decision to look after them ourselves. We’ve sacrificed a lot of personal and social time, but we get to control the kids’ schedules and meals, and make things work out.
I fully understand the need for ‘me’ time, and workout classes are a good way to do that. But don’t make yourself so stressed out about your MIL. Since you say she’s not able to take care of your LO, then exclude her from the equation. Find an alternative, perhaps? Infant care, helper, nanny/baby sitter... multiple options are available, of course with a price. I’m a bit more worried about having other people look after my baby, so I strap mine up on the baby carrier and go walking with my baby to exercise. Haha. And I can easily arrange my schedule to ensure baby sleeps at the right time. Actually it’s quite fun bringing baby on walks with a hipseat carrier:) baby faces the front and is so happy to see everything.
Anyway, see what works for you:) I think as mums, we each struggle too. Your MIL may have struggled when she was a young mum as well, and now she’s afraid of reliving the experience to take care of babies. She didn’t outright say ‘no’ like my mother did. Haha. But it may be very stressful for her. It is for my MIL, so we don’t even ask her to look after my kids full time either. My husband and I just do it ourselves, and the extended family is at peace. Lol.