You can each claim a $250,000 exclusion on the homes you previously owned, or you can claim a $500,000 exclusion on the home where you both now live (which seems to be "her" home from 2019) and not use the exclusion on your home.
Note that marriage imparts ownership but not residency. You are deemed to "own" the 2019 townhome for more than 2 years if your wife does, but you have to figure out how long you have actually lived there as your main home (her ownership attaches to you but not her residency). So whether the $500,000 exclusion on the 2019 townhome is even an option will depend on exactly when you moved in and when you want to sell. If you sell the townhome after you have lived there less than 731 days, you aren't eligible for the joint exclusion of $500,000, only her single exclusion.
Also note that, even if you use your $250,000 exclusion on the sale of the 2017 home, you will still have to pay depreciation recapture on the depreciation you took or could have taken while it was a rental, the recapture is not eligible for the exclusion.
You haven't discussed the likely gains on the two properties, so only you can really tell whether you should pay the full tax on 2017 and use $500,000 on 2019 or use $250,000 each on 2017 and 2019.
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