I think you meant "polygyny" when you said "polygamy". Polygamy means several spouses, who can be male, female, or a mix of both. "Polygyny" means several wives, "polyandry" means several husbands.
While neither of the three means, in itself, that it's a one-way arrangement, many people read these connotations in all three.
Personally, the way I see it, I'm polyamorous and androphile, therefor I'm polyandrous. My husband and boyfriend are polyamorous and gynephile, therefore polygynous. The relationship itself would be polygamous if we all lived together, and currently polyandrous since I'm the only one with more than one partner right now.
However many people could take that as meaning they're not allowed to have other partners, when in this specific case they just don't happen to right now, and in other cases they might have been mono (and it would be just wrong to force someone to take extra partners).
For that reason it's usually best to stick with "polyamorous" and then explain the specific situation so people don't get the wrong idea.