Will I pay Capital Gains or is it considered an exchange?

[Danielle Lueck]

Hi, I'm very new to Real Estate transactions.  Before I make a costly mistake I'm hoping someone can shed some light on what the consequences are of selling my condo.  I purchased 04/16.  My then fiancé purchased a duplex 01/17 and we married 09/17.  I can sell my condo and profit around $100k and house hack the duplex so our max out of pocket each month as long as our rental stays occupied is $300.  

How much in taxes will we pay as a result of the sale?  What are our options to minimize our tax liabilities?

Thanks in advance for your assistance, looking to list condo in December.