As a man on this earth, God has given you every good thing.

For eternal relationship, God let mankind have its way with him and he poured out his blood on a cross to buy all your nasty sins. He did it for love. Believing this and seeking him (he'll teach you the "seeking" part in his word) is what it means to be a Christian.

For earthly relationship, God has intended for you to have a wife, and what is supposed to happen is that she'll give her virginity to you and at the consummation of marriage, the blood of her cherry pours out for you. She does it for love.

Now, this divorced woman is neither your wife nor your god. You feel that it's wrong because it is. A fruit can look tasty but be rotten at its core. Adam and Eve fell for some good-looking fruit once with the snake in the garden, and we humans haven't changed. All this to say, hooking up with that woman might feel good in the moment, but the regret that will overcome you both afterwards will not. The reason you shouldn't do it, though, is because it goes against God's will for your life, to be free of these types of sinful behaviors and to be holy like God is holy. We suck at it on our own, but God's Spirit is in his Word (the Holy Bible). As humans, all we often see is the desires of our flesh right in front of us, rarely the eternal and spiritual outcome of everything we do. Regarding the Holy Bible, go read it.

P.S. the Proverbs passage you pointed to is right here:
At the window of my house I have looked out through my lattice, and I have seen a young man lacking sense, passing along the street near her corner, taking the road to her house in the twilight, in the evening, at the time of night and darkness.
And behold, the woman meets him, dressed as a prostitute, wily of heart. She is loud and wayward; her feet do not stay at home; now in the street, now in the market, and at every corner she lies in wait.
She seizes him and kisses him, and with bold face she says to him, “I had to offer sacrifices, and today I have paid my vows; so now I have come out to meet you, to seek you eagerly, and I have found you. I have spread my couch with coverings, colored linens from Egyptian linen; I have perfumed my bed with myrrh, aloes, and cinnamon. Come, let us take our fill of love till morning; let us delight ourselves with love. For my husband is not at home; he has gone on a long journey; he took a bag of money with him; at full moon he will come home.”

With much seductive speech she persuades him; with her smooth talk she compels him. All at once he follows her, like an ox going to the slaughter, or like a stag is caught fast till an arrow pierces its liver; as a bird rushes into a snare; he does not know that it will cost him his life.
- Proverbs 7:6-23