Yes humans are capable of controling their sexual urges. The Holy Spirit is our guide, God is our strength through Christ. We need to stay in close communion with the Lord if we want His help.
Many people are out of control because they don't know God, or because they are not in a close relationship with him and are not being guided by the Holy Spirit.
It's very important to control ourself sexually within marrige. Faithfulness is the basis of marriage. If trust is broken it destroys love and without love, there is no relationship.
When sexuality has no boundaries, it opens the door for Satan and every kind of sin is on your doorstep.
Marriages seldom survive infidelity, no trust, no love, no marriage. When we marry and have sexual relations with our mate we are giving them the most private and intimate part of ourself. When the mate shares this intimacy with another we feel used and defiled. We are no longer the 'precious' one and only to our mate but just one of the harem.
Children learn from their parents behavior.Generational sin is told of in the Bible. When families are broken the children are pulled between the two people they love most in the world. It is torture for them they are the broken children.
Our spirit becomes muddied, polluted and distanced from Holy God.
Our body becomes Satan's playground to torment with disease, mental and emotional illnesses.
The worst of all is the separation from our Holy God that sin causes.