I found a duplex that I could use an FHA loan and then live in one 2bed unit with a roommate and rent out the other unit.

If you buy a 3br/2ba and get two roommates, you'll have a desirable house and probably be living for free.

Basically, you'd have roommates.  

I just don't want a roommate situation.

I wrote up an agreement that they signed (roommates) that they could pay their portions separately, and that if they ever did end up kicked out because one didn't pay, but the other did, the good tenant would still get good references - forget all the details.  

How about if someone is proposing to move in with a roommate to combine income to meet the minimum income requirement?

The setup: Roommates A,B,C signed lease and roommate D agreed to move in a month later and add himself to the lease.  

From personal experience, the issue he had may not have been with you and your girlfriend, but with the "third wheel" roommate.

look into house hacking, you don't need that much of a down payment for owner occupied, and room mates could help pay down mortgage. 

Dealing with roommates is a giant hassle, and students are even more likely to wreck your property.Whether you choose to rent to families or students, though, you need to hone your criteria and your screening process.