Never compare your mate to someone else’s—not your best friend’s or other friend’s—not your in-law’s spouses, etc. Do not ever speak such things to your own spouse about someone else’s: looks, physical attributes, personality, the way they keep house, or parent, or how athletic he/she is.
If an occasion calls for it, it is fine to admire these qualities in that other person, but never compare them to any perceived “lack” you see in your own mate, and do not overdo it! First of all, if you married the one God gave to you, then he/she is perfectly fitted to you and your personality, skills, etc., complementing both your strengths and your weaknesses, (which we all have!).
Furthermore, you are focusing on that person’s good paints while focusing on your mates perceived had points—This is an unbalanced, unfair comparison. The probability is strong that you do not even know the other person’s weak points, because these are generally not displayed in social gatherings, when everyone is on his/her best behavior.
When you develop an admiration for the other person, you become more attracted to him/her, and as a result, often will become less satisfied with your mate, as his/her faults are magnified in your eyes. This originally “sanctified attraction” can lead to an “unholy attraction.” And such an attraction, if dwelt upon mentally, develops into LUST, and “when LUST is conceived it brings forth SIN.”
The danger is real: Sin never travels alone—”It brings forth DEATH” (James 1:15). This death is of multiple consequences: The death of your once loving, loyal, satisfying attraction and admiration for your own spouse— Which potentially can bring about the death of the marriage— Which always brings heavy damage to your children, and to the relationships you have with members of your spouses family, which pleasure in the past, as well as friendships developed through your spouse.
The worst separation this sin brings is that of your own soul from God. While this can be remedied through true repentance and turning away from all sinful behavior from your heart, the pain and guilt it brings are often experienced for a long time. It is not easy to see unfolding before the devastation you have caused to your spouse and loved ones, especially any children involved.
Then there is the effect that your sin has on the spouse and family of “the other person.” Its harm is so far-reaching, and reminders of your sin and its consequences confront your daily—and your great adversary, Satan, is all too pleased to whisper accusations in your ears to wrench more pain from your own wounded heart. Because, you should know, that such sin is “a dart to your own heart!” (Proverbs 7:23, 5:4).
The wounds inflicted on your own soul can rob you of any future joy of a loving, mutually rewarding marriage, because it gives Satan so much leverage in the battle of the mind. Decide right now to cast down every seductive imagination! (2 Cor. 10:4).