If you’re flexible, then I suspect your ultimate destination will be decided by award availability. I’m taking a trip with the Mrs for the exact same reason later this year and with the exact same limitations you mention. Since we didn’t want to spend most of our time in transit, we chose a 3-city route through Germany and Austria.
Since you’re SE, your access to IKK will presumably lead to a greater number of options than was available to me. And your YQ waiver will open up a bunch of AC flights, so you should be able to get to your chosen destination more quickly.
As for ideas, CDG is always a romantic spot and you should find plenty of availability even if you connect through YUL. You’ve got ZRH, MUC and CPH available direct from YYZ on AC metal, although I wouldn’t spend 7-9 days in any of these cities exclusively. There’s also FCO which you can use as a starting point to explore the mid-to-northern bits of Italy — that should totally be doable in your timeframe. I’m no expert on Spain and/or Portugal, but you can do some combination of the two within a week or so. You’ll probably want to connect through FRA to avoid her first up-front experience being rouge