Our daughter’s viola teacher has the same situation. Her baby is now nearly 3. She hired a baby-sitter for the hourse she taught. There were a couple of times that her baby-sitter-who was a high schooler-was unable to come. Those lessons, her teacher called and asked if I would like to cancel the lesson (reschedule or credit the fee to next month) or watch the baby. (I played with the baby) Her baby sitter was a student of hers. She also limited the hours that she would teach so she could get us all into 1-2 days. She also had make-up/extra lessons (competition, audition times) when her husband was home.
Good luck-hope this helped some