The confession of sin is the door through which forgiveness enters. Yet you must know that a mere feeling of awfulness after the deed is not the whole of repentance, for repentance lives as long as faith. It is not a single bitter draught to be swallowed once and finished. I fear your great love for this young woman, though you speak of her as the best thing in your world, may be a love that has stepped outside the bounds God has fixed. For the union of man and woman is a lifelong covenant of marriage, and all that belongs to it, the intimacy of body and soul, is a garden enclosed. To come to God with a sin of infidelity while yet clinging to a relationship that itself needs to be conformed to His pattern is to ask for a part of the cure while refusing the whole. True repentance gives God glory. It abhors the sin because it is against so holy a Being, and it longs to be altogether clean. Have you that repentance which leads you to look out of self to Christ only?
There is forgiveness with God, that He may be feared. Mark it well: forgiveness is not with your girlfriend, nor in your feelings of love or sorrow, but with the Lord, through Jesus Christ His Son. He blots out transgressions for His own sake, and He will not remember your sins if you come to Him with a broken and contrite heart. But this brokenness is not the weeping of a moment; it is a turning of the whole man from every false way. You have made confession of one fault; now let the Spirit search you and confess all that is amiss in His sight. Remember, judgment may produce a carnal repentance which leaves the heart unchanged, but the repentance that is the work of the Spirit is a rainbow made of tears of grief and glances of hope at the Cross. Stand there and see sin forgiven, and then you will repent more deeply than ever.
Now, I would have you hear this with both ears: There is forgiveness. Not there may be, or there might be for others, but there is, present, full, free, and eternal, for whoever will come to God by Jesus Christ. Though you have played the fool, though you have wounded one you profess to love and, far worse, though you have sinned against heaven and before Him, yet the word is sent to you: "I, even I, am He that blotteth out thy transgressions." Do not run from Him in despair, for where the offense went, from that very place the forgiveness comes. Yet seize this mercy as a new creature. Let this forgiveness teach you to fear, to walk in purity, and to honor the Lord in your body and spirit. If your love for this woman is true, prove it by seeking her highest good, which can never be found in a path that Scripture cannot bless. Commit your way to the Lord, and let the days that remain be marked by a repentance that builds up what sin has torn down, a repentance that needs not to be repented of.