It’s neither healthy nor necessary to dwell on erotic thoughts when single. For one, you never know for sure if you’ll ever be married. So your time wasted fantasizing could be put to better use modeling and preaching the gospel.
View members of the opposite sex in light of eternity. See them how God sees them. They’re either your brother or sister in Christ to be loved and served, and in whom God sees the perfection of Christ, or they’re a nonbeliever subject to God’s wrath, and in desperate need of a Savior.
Focus on their spiritual needs, rather than your physical desires.
“Therefore from now on we recognize no one according to the flesh; even though we have known Christ according to the flesh, yet now we know Him in this way no longer.”
– 2 Corinthians 5:16
7 But the LORD said to Samuel, “Do not look at his appearance or at the height of his stature, because I have rejected him; for God sees not as man sees, for man looks at the outward appearance, but the LORD looks at the heart.”
– 1 Samuel 16
3 Do nothing from selfishness or empty conceit, but with humility of mind regard one another as more important than yourselves; 4 do not merely look out for your own personal interests, but also for the interests of others.
– Philippians 2