Travel during MBA?

Yes, feasible. I've seen many former classmates fly between locations, for recruiting, significant other, and other reasons. Do what's important for you. One skill we learn is how to make time. You will always feel like you are running out of time; hence, prioritize and make sure the most important things that matter to your life get taken care of first.

Recommend this site to take advantage of amazing travel deals for MBAs and other students (A lot of people I know saved money by using it when needing to book flights and travel around): Student Universe

At INSEAD, classes are packed and it would be very difficult to execute your plan to travel every month to North America. It is possible, but it would be tiring and you would have to miss activities and group work, and even classes. The program is divided into 5 periods, with duration of eight weeks per period. During the first two periods, you won't be able to arrange your schedule, the default is spread through five days. For P3 to P5, it can be done, but it would be very challenging especially as you would also want to consider when your target electives are available, and not just choose the ones that give you a longer weekend.

Given the long flight and the time you would want to spend when you visit, traveling during the very short breaks between periods (usually 1-2 days) would be more practical, in my view.

Hope this helps!

Putting aside the question of whether or not it is logistically possible (it is by the way), I would ask why you would want to do this? You'll be missing out on so much during that time you are gone. You have only one shot at business school and it is really only 16-18 months long (not counting your summer internship). But your fiance a good web cam and you guys will be fine.