I am wondering why my wife keeps saying that being a stay at home mum is such hard work. I am not trolling here - but i frankly dont understand. Seems simple enough to me. I have taken care of my kids and home all weekend before and it's definitely no where as stressful as having a job. Our kid is 11 months and is formula fed. We live in a 4 rm flat.

A stay home mum is not as easy as what you thought spending weekend with the kids only. There are so much more than what you can see. If you want to have the feel of how is it like maybe you can try taking a day or 2 day off and take care of your kids alone. Get your wife to spend time outside during that 2 days so that you can really get the feel out of it.