OK i definitely recommend the US or Canada.
I know many Master's students in engineering in my university, and some have families. They live a difficult life, their wives can't drive and the public transport is not good here so i see their wives often walking around with their kids in their strollers. But at least they are together.
Your wife will have an F2 visa so she can't help you with work. However you will be permitted to work 20 hours a week on campus. In Canada the main disadvantage is that it's really cold, so one gets stuck in the house for most of the year. This can be really depressing when you're in a new country. Places like Texas and California are nice as they have a lot of Pakistani people who can serve as a good support system. Academic system at graduate level is same in Canada/US; i dont know about financial issues.
Go ahead and apply and see what happens first. Who knows what will happen...after you receive a letter, you can decide.