Maximized potential by creating an additional unit that was originally just a "mother-in-law suite" and properly separated units to function as two independent STRs.

Because most landlords don’t follow all the legal requirements to maintain their LLC as a separate entity.So, what else can a landlord do to protect their personal assets from a business lawsuit?

My boyfriend later moved in with me into the second home and about a year later we got married.It is my understanding after talking to a local property lawyer that because 3 requirements were met, the rental property is still considered mine as a sole owner (the 3 conditions being: 1- asset was purchased before marriage. 2- we never lived there together as a couple. 3- all income & expenses for the property were kept separate from joint funds and are easily accountable). 

Instead of telling tenants you have to "run it by my wife" you can say "I have to consult my partner" as if there's a separate investor.

These are two separate strategies and you need to know how to analyze deals when sellers are using either strategy or a combination. 

If he's not actually divorced, and just separated, then he's still on the hook for the lease whether he moves out or not.

I would do as @Dena Puliatti suggested and handle the storage / fees for that separately.  

Are you retired military, or did you just separate after serving several years? 

Would they each report their gain separately or is there a form for all 3?

I am debating on getting a business credit card to separate by personal expenses from my business expenses?