While cycling is not cheap you can make it cheaper by finding heavily discounted sales or closeouts sales. there is a slew of ways to save money from clothing to components to whatever. One way is not to replace ANYTHING unless it breaks and it cannot be repaired; you mentioned replacing the crank, well that's not a good idea financially to replace a perfectly fine or rebuildable crank and since there is a very tiny fraction of unnoticeable improvement going from say Tiagra to 105 to Ultegra to even DA cranks.
Of course if your very wealthy then I'm not sure why your wife would care what you spend on cycling, so this kind of hints that you're probably not among the top 10% of income makers if your wife is having fits, so you may want to consider on how to spend money without making your wife mad. Mad money, you know money that your wife has no clue that you have, saves a lot of various wife emotions when you approach her saying you need X amount of dollars for something. I always have about $200 to $500 hiding in case I can't approach her with buying something with her knowledge, this saves me from hearing her go into why we don't have the money right now routine. Yeah, she does the books because she's better at it then me. I just recently bought a set of SPD pedals for my touring bike without her knowing, this sort of thing she has no idea what pedals I had before or after I replaced them, and thus it's easy to hide the details from her without her knowing I have money somewhere. I also bought walkable shoes to go with the new pedals, she sort of noticed the shoes and asked if they were new, I said no I had them for a while just don't wear them much! LOL!! She was fine with explanation, never said anything more about it! The shoe thing did press my luck a bit but I won. Technically I wasn't lying to her when I said what I said because once I bought the shoes they were no longer new, and having them awhile could mean anything for a day to years, and I hadn't worn them much maybe a couple of times! LOL!! Anyway that's one way of taking care of the wife having issues with money being spent. My wife is tighter than I am and I'm a tightwad, so to avoid conflicts I go by the old saying that what the wife doesn't know won't hurt you, and thus there is peace in the house! LOL!!