Partner? As in he is an open ɧoɱosɛҳųαƖ?

No, a woman. 

Could they stay in a hotel/airbnb? 

That’s not really the issue because they would do that anyway. The issue is telling them they can’t both come into the house.

These situations are very difficult.  Have you talked to a priest to see what they have to say?

I guess I don't understand why they can't both come into the house at the same time.  If two people came over and you said this is so and so and this is their friend so and so, then they would get the hint that the relationship should not be discussed.  Why would they discuss the intimate details of their relationship to a child?

...Accidentally posted as anonymous...
Are we as Catholics supposed to cut off any relations with a neighbor, family member, etc due to our conversion to the one true Faith? I've got friends that I associate with that are not Catholic but at the same time we don't engage in anything improper, i.e. movie watching, bad bars/restaurants, etc. Should they decide to do something like that, I simply bow out of it. But if the getting together is because we've been long time friends and it's for dinner and friendly get-togethers, is telling them "no, I can't do that because you're not a traditional Catholic and until you become one, we can no longer associate with each other!" Jeez, our Lord ate with sinners all the time. I do limit my times with them but I most certainly will not disown them, they may need my temporal/spiritual help one day and I want them to count on my support.

If the situation is for the children, important to make sure the Catholic children are made aware of right and wrong things to do/not to do and if they're fairly young, then some sort of supervision would be needed.

Just my 2-cents...

This is completely different than the OP whose family and friends "lead bad lives and are occasions of sin."

"lead bad lives and are occasions of sin."

If they are "occasions of sin" for you, then this is your problem.

this is an on going issue for many in different ways.  Number one, you give example.  Example, we don't shack up in our home, find a hotel.  Our please don't come, your example is effecting the family.  Since when do we feel we might need to say nothing.  Get your backbone and just put it on the table.  In this house, we serve God.  Your ways of drugs and sɛҳuąƖ pervergen is not wanted.  

We are not going to feel like we are hurting feelings.  Those who test you, need to be told up front, it is you who is against God, and we will not compromise, and will show you the door.

Some of these perverts, the Sodom and Gomorha group have fun tricking you and testing you and getting their laughs.  Make sure you show them the door, it is your home!  Even if they are family, same thing, show them the door.

If you ever feel that you wish you would have said this or that, you know you need to do it and once you do, you can rest easy!!

I have had to deal with this for over a decade, since our conversion. When my father remarried (parents are divorced ) he sent a letter to my children signed by him and his new wife. I had already agreed with my sister that we would not congratulate him but she went ahead and congratulated him anyway, so I was really on my own with this one. 

I wrote back to let him know that his new wife had no direct relationship with our children, explained the religious angle and that while I wanted him to know his grandchildren, it was none of her concern.  I also explained that I have sisters living with boyfriends and were told that they would no longer visit us as couples. 

This of course went very badly and in his email reply he copied in everyone in the family and the mail started by saying what a pontificating judgemental person I was. I left the exchange there as his reply was so extreme and there was nothing let to add to my first letter. 

Although I regretted the letter I wrote at the time, in retrospect I think it was the right thing to do. We have met several times and also with his wife but they have never stayed with us.