The world is full of moral decadence and ungodly images of sex. The fact that it feels right does not make it right. You must resist sexual temptations in every way.
“Flee fornication. Every sin that a man doeth is without the body; but he that committeth fornication sinneth against his own body.” – 1Corinthians 6: 18
“Flee also youthful lusts: but follow righteousness, faith, charity, peace, with them that call on the Lord out of a pure heart.” – 2Timothy 2: 22
“Abstain from all appearance of evil.” – 1Thessalonians 5: 22
“Submit yourselves therefore to God. Resist the devil, and he will flee from you.” – James 4: 7