I am Canadian Citizen. So I can understand when someone breaks all ties to Canada, has nothing to do with Canada, and exclusively lives abroad.
But I have everything in Canada, except I had to move abroad to live with my fiancé.
So as a citizen, you can sponsor from abroad.
The most significant difference of marking whether you exclusively live abroad is that as a citizen-sponsor abroad, you'll have to show your intent to return to Canada. Given everything you've said above, demonstrating that shouldn't be difficult at all.
You haven't indicated how long your 'temporary' move to join your fiance/spouse has been, and how long you expect it to be. Ultimately you'll have to decide how to submit.
If you want a
guess - here's how I'd look at it; less than six months total is pretty easy to defend as temporary (in this context), more than a year is living somewhere else. In-between - may depend on circumstances but harder to delineate - if someone had already returned and was saying their 8-month sojourn was temporary, sounds plausible; if it remains open-ended (i.e. not yet returned but just a plan to keep at 8 months), I'd be skeptical.
You can write a letter of explanation either way. Note that I don't think there's any clear indication either type takes longer, but IRCC
seems to be routinely asking citizen-sponsors abroad to update their plans to return towards end of process. (And invariably a fair number of those sponsors have actually not made much preparations and that request comes as a surprise and freaks them out).
Note also: don't know your plans but you can apply for TRV for spouse, and if granted, return to Canada together earlier. And if you do return to Canada during the process (to stay), advise IRCC - actually having returned is very good evidence of intent to return.