Visual Custom Content
Custom clothes, custom objects, modified user interface, edited game tuning files, or other custom content can cause the game to crash!
Additional content for WickedWhims like sex animations, penis mods, detail body skins or extra objects are no exception to this rule, although they are generally tested. Custom Content is generally the most common issue of the game crashing. Anything visual is handled on the client-side meaning any rendering problems will result in a game crash.
Scripts are almost never the issue of the game crashing.
Make a copy of your saves (\Documents\Electronic Arts\The Sims 4\saves) and try removing all Custom Content you have. Load the game afterward and see if the problem persists. Remember to remove everything, don’t assume that something can’t cause issues, no exceptions!
Majority of reported crashes come from Mac users, which can point to possible instability of the game itself. If you're a MacOS user, consider that your game might be having stability issues and that there might not be any solution for it.