Maybe this will be too general, but I want to share my first impressions I get whenever the topic about the different relationship styles is talked about. I wondered about the different perspectives as well when things started. But it came down to some simple things the longer I (and I am able to say We here as well) thought about it and let it sink in.
The wish, desire, need to love. Each of us (poly-me, mono-husband, mono-other-spouse) desire to be with the person we love. Fullstop. Regardless of how many there may be. There is no condition to this first aspect, just love, feelings and being true to them.
After this, the condition enters the game. The question of 'how' we want to love and more importantly, how we want to be loved, stands a whole different page. And another one is the way each of us pictures this wish to come true. I had to learn, that even if my wish my differ from the others' wishes, that I can't make a value judgement about theirs because they are different from mine. And in the case vice versa as well. What does it matter that I don't understand how the other person is loving me? (Talking about the point of view of my boyfriend here, he clearly stated that he can't imagine how it would be like to love more than one and how that has to be for me, but he doesn't care about this lack of knowledge as long as the next condition is in place: ) The most important fact is to feel loved and be satisfied with that.
That's why I always think about the point of arguing about different relationship styles. There seem to be cases were they work. There are people satisfied with different relationship in their life. No one can tell you how you yourself would feel in this situation, therefore each of us has to find the individual path to happiness.
Thinking about how this works in a successful and mutually fulfilling mono/poly sitch. Perhaps the mono cognitively grasps the poly's perspective and just lets go and has faith?
I guess this is simply true for all relationships. You need to have faith in the feelings the other person is showing you and have faith in the way this resonates with you. You will never be able to 'control' or get some solid proof of the real feelings of your partner. Those are his, you can only judge the way this evokes feelings within yourself. And if you feel satisfied with that. That's how our 'mono/poly sitch' works.
It took time as all changes need some time to become normal and processable. The answer wasn't there immediately, so don't worry about not having a clue what your feelings want to tell you right now. Just keep listening to them and sorting them out. If you come out in a place where you are able to feel comfortable, things are fine. If not, search for the things missing for you. This, again, will just need some time.
(As I said, purely my take on the matter and maybe a bit too general for an answer.)