A example would be a boy friend and girlfriend live together and adopt two unrelated children, that is four unrelated people by blood in a household yet they live as a family. 

., but I’m not sure if that still makes sense.During the closing process I learned that the property was still occupied by the previous owner that was foreclosed on and that her and her boyfriend were drug addicts and at least one of them had a warrant out for their arrest.

This tenet was the only unit we couldn't get access to ( someone changed the locks) my pm went to speak with her the next day to see if she has a key, and some dude that wasn't on the lease ( guessing her boyfriend) answered the door and said they never got a key and they never used the storage unit. so my pm assumed it belonged to the previous tenant. so we had the handy man pop the locks the gain access for the appraiser.

My tenants have broken up and both agreed the boyfriend will move out.

I guess 'burned' is relative; I picked one girl that let her boyfriend(s)?

I will be investing with my long-term boyfriend-- we planned to get a single family that was not in good shape, but inhabitable, live in for a year while renovating, and then moving out and making it a rental property.

I had doubts about moving in with my boyfriend.

In the unit next door, one of the tenants was already practically living with her boyfriend and was willing to break the lease early, paid for all of March and actually moved out in early March giving me the chance to do some minor upgrades, have showings right away and get it rented to limit vacancy.

For example, you can't give a holiday gift to only who you think are good tenants because one of them would post "Thanks Sam for the $25 AMC movies GC my boy friend and I saw Avengers last night xoxo" then your other tenants who didn't get a GC will feel left out.I visit my properties once a month for regular maintenance, mostly for little stuff, like changing AC filters, test smoke alarm batteries, test GFCI receptacles, pour bleach down AC condensate drain lines, exercise water supply stop valves, feel under any drains to check leakage, test water heater T&P valves, etc etc etc...they do not need to be done monthly but that's what I do at each property. 

So with a recent tenant moving out I’ve since discovered that she had a boyfriend staying with her in my property.