I am a firm believer in non-standard relationships at this point, monogamous or otherwise. The reason for this is because people are freer now and the modality of life has changed a bit. People feel entitled to variety now, as they should be. So yes, it can work. Standard relationships usually faily anyway.
I believe if the two individuals go into the relationship with a clear understanding of what a non-standard monogamous relationship is and they both desire to have that type of relationship then I see no reason why that relationship could not work, It will not work if one party says they want it but secretly want something else but besides that it would work fine.
Yes, I think that there is not a relationship out there that will not work, and that all that you need is two people that are really in love and that are always happy when they are with the other person, and that they support them in all that they do.
I believe it is possible for non-standard monogamous relationships to work. I believe these relationships can work if all the parties involved understand what is going on and agree to certain terms. This works better for some people. It's certainly not my cup of tea and it wouldn't work for me, but that doesn't make it impossible.
No, I do not think that non-standard monogamous relationships can work, because there is something about them that is unnatural, that ultimately makes them fall apart in the end. Take for example, Ashton Kutcher and Demi Moore. The large age gap ultimately led to their breaking up. Traditional marriages work because they are made in a way that works.