Quath! You didn't suggest that he do some reading on here! Sigh.... my job, I know... on it.
I suggest that you do some reading on here in order to become familiar with what poly experiences others have had, what works, what doesn't... there are some great threads if you do a tag search for "lessons" and "foundations" to start...
I was wondering a few things about your story. When are you going to move to be together? Is this marriage always going to be distant, or are you eventually going to be in the same place, live together forever kind of thing? That would make a huge difference to where this poly experience is going I think... if you have no future plans for move closer then I would think poly could work really well for you, if you intend to move to be together, then I would suggest waiting and working your ass off to get to the same place before taking on another lover... complications could arise if you were to leave this new lover behind etc etc... lots of drama could go on there.
The other point is, and Quath touched on this too, is that prescribing a version of what poly is on each other is dangerous and can be disastrous... people generally do a lot better in poly if they decide what it means to themselves personally, have a description of what poly is to them. Creating a triad and expecting that you have the same taste in men and that everyone will love each other equally is a lovely thought, but not very realistic it seems. Finding a separate partner that is a good friend/metamour to your husband would be more realistic... still, wonders never cease to amaze. Never know.
Lastly, what of his relationship life. Would you be okay with him finding a partner other than you? This sometimes can really help make or break a decision, because what you want/need should not be yours alone I think... he is entitled to the same no?