We chose it very deliberately to raise our kids on one income. That meant we were not going on expensive vacation, buying just because we could. Our kids wear hand-me-downs, we ride an old car and I don't buy a shirt for myself if it costs more than a few dollars. We live frugal life but we are not cheap. We cook healthy meals at home and don't eat out, we reuse, We carefully decide whether we want something vs need it. Our kids still go to extracurricular classes but not to all that are available. We try to live simple life and make our ends meet.
You also need to take into consideration that if mom works, she has to incur certain expenses that we don't have. For example, she needs to have a better selection of quality clothes, she needs more gas to drive to and from work, she has to pay the childcare expenses. Working mom has less time to cook so she pays higher price for take out foods, uses on average more professional services than a SAHM because her time is limited.