I have a 2006 M35X with about 184k miles on it. I have to add a quart of oil every 2-3 weeks. I never see any oil stains on my driveway so I don't think it is leaking out and I don't have any smoke coming out of my tailpipe indicating I am burning it off. Where is my oil going? At $10 per quart of synthetic oil it's getting expensive and it a nuisance to have to constantly add oil. Any thoughts on what it could be?

And how many miles do you cover in this time period? Is it a lot of stop-and-go traffic?
Do you know if your PCV valves have been serviced recently?

If you can represent the oil consumption as quarts per miles, it could help determine if it's normal or not.

I'd probably say around 500-600 miles over that time period. Yes, it a lot of stop and go traffic as I slowly make it up the I95 highway for my commute to/from work. As far as I know, the PCV valves have not been serviced. I've never done them and I've had the car for almost 5 years.

May I ask what your oil change (mileage) interval is?

Usually I change the oil around 3500-4000 miles. But honestly, with me constantly dumping quarts of synthetic into it I've been pushing it closer to 5k miles on the last two oil changes.

As EdBwoy said, PCV valve system check is first.
If all OK with that, I would switch to a dino oil, like 5w-30 for one oil change, and see if you burn less with that over the synthetic, (presuming you are burning the oil and not leaking it elsewhere)
On older engines that start to wear, the finer molecular structure of synthetic oils tend to flow more freely past worn components.

If the cause of the oil loss is from worn piston rings or glazed cylinder walls, using dino oil will help a bit, especially if you are using a synthetic oil lighter than a 5w-30.

I have had my m35x since new, never a drop of synthetic, it has 160k miles on it.
I would say I burn a quart of oil every 3k to 3.5k miles depending on driving conditions.

Thank you both for your guidance. I changed my PCV valve over the weekend and plan on doing an oil change with conventional oil next weekend. I'll report back in a few weeks to see how my oil levels are looking.