She shouldn't have to hide who she is, and she should be able to come out to her friends and be accepted. They don't have to agree with her sexuality, but they should accept her for who she is.

Of course her friend has the right to set rules as to who can come to her party, or her house, or whatever. But that doesn't mean it isn't disrespectful.

You talk about respecting others' boundaries and feelings...well, what about Lexicon's boundaries and feelings? Why can't her friend respect her? What if, instead of being bi, Lex was the mother of a mentally retarded child. If her friend didn't want mentally retarded children in her home, she has the right to make that rule, but is that really the person Lex should have as a friend?