Zig Zagged: Bob is a very loving and attentive father, and he's also extremely good at his job and is an excellent provider. The problem is that he's also as stubborn as a mule when it comes to trying to fix something himself when it breaks down, rather than calling a professional. On those occasions, his competence flies completely out the window.
One of the parents needs to be somewhat on the ball for the sake of Conservation of Competence, and you want the characterisations to be relatively consistent rather than a constant game of Idiot Ball. You know that every time the dad is shown to be somehow "superior" to his wife, you'll have a protracted battle with the Moral Guardians, but not so the other way around. What are you gonna do?
Lampshaded: "He's like all those bumbling dads you see in sitcoms."
Invoked: Alice specifies in her Lonely Hearts ad that she's looking for a Man Child with whom to settle down and raise kids.
Exploited: Bob deliberately makes it look like he can't do anything right around the house so he doesn't have to.
Alice breaks up with Bob when she sees that he is too immature to raise a family, and not likely to change any time soon.
Alternately, Bob decides, "Enough fooling around; I'm expecting kids soon.", and spends more time with Alice. He also learns basic household chores from her...
Discussed: "I hope Bob Jr. doesn't inherit his dad's bumbling tendencies. It'd be a real hassle when we're married."
Conversed: "Seriously? Another bumbling dad show? I'd like to see a competent, take charge father on a sitcom for a change."
Deconstructed: Can have a negative effect on his children and his wife, leading to the breakdown of the (presumably already dysfunctional) family.
Reconstructed: Bob is dumb and irresponsible, but he sincerely loves his family and is capable of stepping up when it's important.
Played For Drama: Bob's mistakes and selfishness negatively affect his family.