I do think in terms of primary/secondary, so online I would explain it in that manner, so people would know who I am refering to.
In real life, When we had poly dynamics going on, I had a 'hubby' and a 'hunny'.
I also found saying 'boyfriend' or 'girlfriend' had a special uniqueness to it.
To me, the bf/gf label, has a fun innocence or purity to it, that stops people from concluding ; ' fuck buddy '.
Unlike other pet names, which might seem to vague.