I think federally at least sexuality is a protected characteristic, but I don't think the courts in Idaho would respect that so you'd need to have the funds to appeal it up a few levels

Btw the ruling to make sexuality a protected characteristic was an incredibly rare Gorsuch W where he ruled that discriminating based off of sexual orientation was discriminating based off of sex (i.e. if you refuse service to Jim because Jim dates Bob, but you wouldn't refuse service to Jane because Jane dates Bob, then that's implicitly discrimination based off of sex)