A wise husband or wife who loves God and wants to be obedient, loves their spouse and want to earn and demonstrate trustworthiness will have no problem adhering to healthy boundaries in their marriage.

Self control is important, it is a fruit of the Holy Spirit in us, but boundaries, to avoid the traps of adultery and sexual immorality, are essential too.

It really has nothing to do with insecurity but everything to do with being holy and set apart for Christ and your spouse.

1 Peter 1:14-16 NIV
[14] As obedient children, do not conform to the evil desires you had when you lived in ignorance. [15] But just as he who called you is holy, so be holy in all you do; [16] for it is written: “Be holy, because I am holy.”

Hebrews 12:14 NIV
[14] Make every effort to live in peace with everyone and to be holy; without holiness no one will see the Lord.