"Hate the sin, love the sinner" has been a popular phrase for quite some time. And how true, especially when you consider we are ALL sinners!
It is only through the repentance of our sins, and asking Jesus into our hearts, does that change once and for all. Have you taken that crucial step yet? If not, don't wait! (Romans 10:9-10)
Basically, what that popular saying means is that we can disagree with what that person is doing, but we can still love them. Amen. Even though we still love that person, there are also times, "loving them", means speaking the truth about what they are doing (whether they want to hear it or not).
"Dear friends, let us continue to love one another, for love comes from God. Anyone who loves is a child of God and knows God. But anyone who does not love does not know God, for God is love." (1 John 4:7-8)
Never shy away, nor feel bad about, speaking a truth that can save another person's life for all eternity! In the end, what they are doing is between them and our Lord and Savior. But just think, God may have put YOU in that person's life to tell them "exactly" what they need to hear!
Don't shy away from the truth, as it is that very truth you speak that may "finally" set that person free. (John 8:32)
"For I am convinced that neither death nor life, neither angels nor demons, neither the present nor the future, nor any powers, neither height nor depth, nor anything else in all creation, will be able to separate us from the love of God that is in Christ Jesus our Lord." (Romans 8:38-39)