Hi!
Unfortuantely this happens to large numbers of Mac simmers. Although the most recent patch did improve the performance of TS3 on Mac OS X, it didn't fix this problem. At the moment my game is running pretty well, but I still get the dreaded exception raised problem from time to time.
Choosing either Yes or No makes no difference. Whichever you pick, the game will close. There's a fairly big thread (and many small ones) over on the forums:
http://forum.thesims3.com/jforum/posts/list/48717.page
Have you tried purging your RAM? It makes a big difference. BluebellFlora has a guide on her website about how to do this. There is updated information there if you have upgraded your operating system to Mavericks (as you have to do something slightly different) but there is also information on how to purge RAM for other versions of the OS:
http://bluebellflora.com/the-sims-3-on-a-mac/resetting-ram-during-gameplay/
When I open TS3 launcher, I watch on Activity Monitor and see the amount of free RAM plumet. So then I purge the RAM before pressing Play on the Launcher. Once I'm past the startup screen, I press cmd-return to make the game go into windowed mode. That way I can keep an eye on Activity Monitor while the game loads. While I'm actually playing, I like to be in fullscreen mode, but occasionally I go into windowed, check the RAM, purge if necessary using Terminal, then go back into windowed. I also turn to windowed mode while saving (so if it freezes, I can force quit) and before going into CAS (as that is a common time for it to crash).
