Tenant's Girlfriend Staying Too Much?

[Rachel H.]

Hi everyone. I have a great tenant. He's responsible, responsive, takes good care of the place, pays on time, etc. I've recently noticed, though, that his girlfriend stays over several times a week. She also has a small dog who stays as well, from what I can tell (my tenant has a larger approved dog; it's a pet friendly house, but I only have one dog deposit and one approved). She is not on the lease. Should she be? When does it become an issue? If, say, I'm not worried about him damaging the place and I'm not too worried about the little dog doing damage that the big dog wouldn't do (and I'm not particularly worried about the big dog), should I even make an issue of it? First time dealing with a situation like this, so wondering what folks recommend. Thanks for any advice and guidance!