It's not idolatry to desire love/relationships/marriage, and it won't be idolatry as long as you commit yourself to the Lord with or without this person. Pray to the Lord about this person you have in mind. Sometimes other people meddle into other people's lives and try to stop what God may have blessed him or her with and try to assert their will on them. Pray that no weapon of the enemy will prosper if you and this person really are a connection that the Lord would bless and that the condition of your heart and emotions will be okay no matter what happens. The Lord knows you better than anyone. I pray whatever outcome would work best for you. In Jesus's name, Amen.