I have experience of this type of situation which ended badly.
I was living by myself, and the married couple I was dating moved in. Long story short, she moved out after a year (she didn't like the rural setting). and he's been lingering for almost a year.
The physical relationship has been over (with all three of us) for the past year.
Have regular house meetings... this keeps communication open about the basics.. household chores, status of bill payment, schedules. We were having regular meetings but....
We celebrated accomplishments (got the back porch cleaned!!) and reviewed plans (Convention this month...need to cut grocery costs by $20 to help pay for the room...
Some of my best memories are from those meetings where we were giving praise, and goals for the next week.