You cannot gain victory over lust if you're fighting the battle secretly.
Our natural pride tells us, "You can do it on your own." God's Word--and experience--show otherwise. God gave us families and churches specifically because we can't "do it on our own".
Allow me a few quotes:
12 Beware, brethren, lest there be in any of you an evil heart of unbelief in departing from the living God; 13 but exhort one another daily, while it is called “Today,” lest any of you be hardened through the deceitfulness of sin. (Hebrews 3, NKJV)
16Therefore confess your sins to each other and pray for each other so that you may be healed. The prayer of a righteous man is powerful and effective. (James 5, NIV)We confess our sins to God for forgiveness but confess our sins to other people for accountability.
5 This is the message which we have heard from Him and declare to you, that God is light and in Him is no darkness at all. 6 If we say that we have fellowship with Him, and walk in darkness, we lie and do not practice the truth. 7 But if we walk in the light as He is in the light, we have fellowship with one another, and the blood of Jesus Christ His Son cleanses us from all sin. (1 John 1, NKJV)My Dad likes to say that secret sin is like a loaded gun pointed at your head, but when you share your sin to another mature believer who will hold you accountable, the bullets fall out of the gun.
I will not elaborate in detail because many others have written excellent articles on this topic. Here are links to two:
Accountability, by Kenneth Boa
What the Bible Says about Accountability -- GotQuestions.org
The point is, if you have secret sin, get it out in the light. Take the power out of the secret! Find freedom by humbling yourself before God and men!