We are taught in our lives to share. Some of us do good jobs. Others refuse to do so at all. But there are some things in life we are not supposed to share. God did not intend sexual favors to be shared with except in the concept of marriage. And in these verses he is really emphasizing not to exchange those favors with a married person.
Drink water from your own cistern,
running water from your own well.
Should your springs overflow in the streets,
your streams of water in the public squares?
Let them be yours alone,
never to be shared with strangers.
May your fountain be blessed,
and may you rejoice in the wife of your youth.
A loving doe, a graceful deer—
may her breasts satisfy you always,
may you ever be captivated by her love.
Why be captivated, my son, by an adulteress?
Why embrace the bosom of another man’s wife? (Prov 5:15-20 NIV)
Keep your sexual life pure. Keep your marriage (or the other person’s marriage) pure. When you cross that line and enjoy the forbidden of another man’s wife or another woman’s husband (because despite the pronouns used, ladies, these words are meant for you also), you have done several things: 1) you have insulted the other man by taking something that was personal and close to him – basically you stole from him, 2) you soiled and contaminated the other woman – you are not her husband, 3) you have insulted your wife more than anything else could have – you said that she is not adequate, 4) any children involved will look with disdain upon you and will not give you the respect your position of father should receive, 5) you told God that He is not all knowledgeable and you know more than Him. Is any of this worth it? But, no one will know you say. Let me first say that I’ve never hear of an affair that involved only 1 person. You sleep with your neighbor’s wife and there were two of you. Already the cat is out of the bag. The more you sleep with the more that know. You cannot control all circumstances. You cannot control everything. No matter how confident you feel right now as you “succeed” in eating your cake and having it, too, you will be one of the many losers in this.
Go to your wife (husband) and start dating again. Over the years everyone changes and new aspects of themselves are revealed. Explore those. Be adventurous with your wife. You’d be surprised what wonders you can find with her.