My wife always compares my parenting with her sister's husband's parenting and thinks he is a much better father than me. I find this comparison annoying and heartbreaking. How do I make her understand this?

I don’t see a point to compare , it’s pretty sensitive to compare with relatives . It would be great if you can share what causes her to say that ? To me it sound like she needs your help when it comes to parenting hence she’s comparing . If not I don’t see a point in comparing 😂 talk to her and try to find out what she really mean . Always remember nobody is perfect and educate her as well , we are humans not robots and we don’t change over night or become better after being compared lol.