Ahh, Bonaire!
I've been to Aruba and Bonaire (diving and vacationing). My knowledge of Curacao comes from dive buddies who have went there and compared it to A&B.
I think your decision should be based on whether your SO will be diving with you or not. Assuming they also dive...
I would recommend going first to Bonaire and spend at least 9 diving days there. Between the diving, restuarants, pace and weather I can assure you that you will not want to leave
Then I would recommend hopping back to Aruba for 3-4 days and just relax. This will ease you into your PBD! Your SO will probably find this to be a great ending to a dive vacation. And on your last day, you'll be heading to a big airport with lots of flight options so you won't be ending your trip worrying about prop-jet hops, connections, luggage, etc. If you still have the diving bug, just do a couple of dives while in Aruba. They are interesting but they will not compare to Bonaire (IMHO). We like staying on the other beach (Eagle?) in Aruba where there are less high rise hotels. There are some fantastic restaurants there as well (ie Flying Fishbone, etc).
I think I would skip Curacao if I only had two weeks, partly because of feedback from friends who have been there and partly because added hops cost you diving time.
And, if you have a really good direct Jet flight option out of Bonaire (skipping San Juan, no inter-island hops, etc) and your SO is a mega-diver (like you) I would reverse the trip starting with a 2 or 3 day mini-vacation in Aruba followed up by 10 or more days diving in Bonaire.
If your SO is not a diver at all, spend a few more days on the other islands and few less on Bonaire - but that will not be easy for you!!!
Bonaire is a gem. As soon as the plane lifts off you'll be wanting to go back