Thanks everyone for the advice and warm welcome. I do believe in listening to my inner voice - the one that doesn't want to open my home to Betsy - but there's another voice that tells me I should be supporting my friend, and that I'm being selfish. She's a very sweet person and loved by all.
I called another friend today who has known Betsy since she started NA about 15 years ago. He told me that she didn't make a conscious choice to relapse, that it is her disease that made her do it. That her disease doesn't care that she just moved into a recovery house where they drug test her everyday. That made me feel guilty for not wanting to help her. I know it's harder for some people than for others, especially when the DOC is heroin.
All that being said, am I guarding my recovery by not giving her a place to stay or am I being selfish? Sorry if I'm being redundant. I'm only 15 months into recovery and don't make decisions very well yet. Thanks for any feedback!