I had similar problem.
I am pretty sure you are going to find this post at the end of the thread after slogging through all those helpful posts suggesting that you show your wife who is the boss ;-)
I had similar problems (with computer, not with my fantastic wife!) some time ago and I have solved them by cutting several large holes in the side of the case, installing large fans (12 volt versions, I ran them at slightly lower voltage) and installing a cardboard ducts that directed the airflow directly to the graphics card and to the processor cooler. Take care to provide also air outlets to keep up with large fans blowing in. The best way to let the majority of the air out is through the power source.
I was also able to run those [multiple] large fans off 7V that I got by connecting them between 12V and 5V lead on a power source. Be careful, "your mileage might vary" and your power source might not like being used this way. This was suggested to me by a computer technician that works for the same company I do.
It also helps processor has heat-pipe cooler. Heat-pipe is a copper pipe filled with a liquid and sealed tight, with no external means to circulate liquid. They are used extensively in notebooks and luxury coolers. It works because liquid has better heat conducting properties than copper. Pay attention to the orientation of the cooler suggested by manufacturers - some of them are said to work only in horizontal / vertical position and not upside-down.
Consider getting an SSD. Much quieter than a HDD and you might get computer that feels actually faster even if you under-clock your processor.
Consider replacing small cooler with fan on a chipset [if you have one] with a much larger [passive] heat dissipating cooler. Combine with a large 12V fan fed by 7V or PWM power source blowing on it through cardboard air duct.
Consider building / buying a small PWM power source with variable output that is powered by 12V from PC. I believe those are available commercially for modders, complete with thermal sensors, but building one (without thermal regulation) can be a fun little Sunday project. The PWM source then powers your fans, so they spin fast enough to cool your PC and slow enough not to make much noise. You turn it all the way up before serious gaming session.
Consider under-clocking your processor AND graphics cards when you do not play on your PC.
I have recently purchased a notebook as a replacement of my big rig that had many of the above mentioned enhancements. I bought a notebook, because I was visiting USA and I wanted to buy a better computer there during Black Friday and I strongly disliked the idea of packing a regular desktop PC inside a big checked-in suitcase. So I had to purchase something that I could take with me alongside a company-issued notebook. I had a *strong* case of buyers remorse. Now I can't improve my computer anymore. No installing extra stuff, getting a second disk (large SSD) was complicated and I had to give up [internal] DVD drive. On the other hand, notebook *is* much quieter, especially with an SSD.
So, if you like to tinker with your big rig, like I did, do not make the same mistake. - Unless you are filthy rich and can afford an alienware or similar notebook ;-).
Would Parallels running on the newest 4k iMac be powerful enough for your games? [evil grin ;-)]