Most Helpful Guy
Monogamous relationships are not unrealistic upon themselves, what's unrealistic is people in general, people nowadays want instant gratification without putting in time or effort, but with people with patients and willing to work out issues together and understand, monogamous relationships work just fine.
Most Helpful Girl
I haven't had difficulty maintaining a monogamous relationship. If both partners value monogamy, I don't see a problem. Of course, I live in a country where polygamy is very much frowned upon, and most people look for a monogamous relationship anyway. Makes it easier.