The Bible contains a multitude of warnings on adultery and other forms of sexual immorality. There is good reason for this; even secular sociological and psychological once acknowledged and understood the far reaching damage that can be caused by such acts, both mental and physical. Those that perform these acts are often attempting to fill a void in themselves that they do not quite understand; thus they attempt to do so through poorly-thought and unwise carnal means.
1 My son, be attentive to my wisdom;
incline your ear to my understanding,
2 that you may keep discretion,
and your lips may guard knowledge.
3 For the lips of a forbidden woman drip honey,
and her speech is smoother than oil,
4 but in the end she is bitter as wormwood,
sharp as a two-edged sword.
5 Her feet go down to death;
her steps follow the path to Sheol;
6 she does not ponder the path of life;
her ways wander, and she does not know it.
7 And now, O sons, listen to me,
and do not depart from the words of my mouth.
8 Keep your way far from her,
and do not go near the door of her house...
In the book of Matthew, Jesus further expanded the definition of adultery past the physical and into the mental, making it clear that this is not only an issue of misplaced desire, but an issue of the heart:
27 “You have heard that it was said, ‘You shall not commit adultery.’
28 But I say to you that everyone who looks at a woman with lustful intent
has already committed adultery with her in his heart.
-- Matthew 5:27-28
I've had conversations with people about this. While I freely admit that I am not immune to adultery in the heart (I believe every last man on earth, with the possible exception of eunuchs, could not truthfully say that they are), I do have some specific guardrails against physical adultery that at least help in ensuring that I have an extra edge of protection against it. Some seem to think that by that, I mean that I don't have to worry about it. By no means is this true.
My parents divorced in my early teens - I caught my father unmistakably in adultery with someone I think he met while on TDY as a DoD civil servant. Apparently someone underestimated my proficiency with computers at even a young age and I accidentally stumbled upon the evidence. This discovery practically devastated me during the hormonal upheaval of puberty - I went so far as to joining the football team with the soul purpose of simply crushing opponents (guess who ended up on the defensive line). This was also the time where I effectively became an atheist.
This single act stuck with me. I vowed to never, ever, do that sort of thing to anyone under the pain of death, and I took it that seriously. While I don't go so far as "to the death" today, I do still keep vigilant watch for it. I have a couple of examples that make this abundantly clear.
One that I am not proud of but nonetheless admit to and own, happened in my early 20's when I was dating a girl. We were at a friend's apartment for a get together. Everyone was consuming alcohol and I had my usual more-than-fair-share. At some point, I ended up upstairs, I think it was to use one of the restrooms. I ended up talking with people and eventually everyone dispersed except this one girl, who attempted to "woo" me, for lack of a better term. I remember gently rebuffing it until she started physically touching me, whereupon I grabbed her, dragged her downstairs to the host, and told him something like, "if she comes within ten feet of me the rest of the night I will show her how serious I am about not cheating." I'm not proud of that sort of conduct, but it did get the point across quickly, decisively, and without further incident.
The other one happened in my mid-20s, within a group of hockey friends. There was a husband and wife pair that were good friends - we all spent a lot of time together at hockey games (both pro and amateur as the husband and I were beer league players), get togethers, and other random functions. Needless to say there was a lot of interaction between all the members of that group, bound by the love of hockey. The wife of this pair also happened to be my age and did marching band / winter guard in high school, so we'd often talk about that. Come to find out, we both had actually performed at some of the same competitions in Georgia. So naturally, we found a common band thing to nerd out on. The relationship was strictly platonic, neither of us flirted with the other, and we were never around each other without the husband also being there or nearby. Eventually, at some point, the two of them separated and divorced. Playing in a hockey game with each other at a later point (on the same team, too!), he confided in me that he actually thought she was cheating on him with me. We had a heart to heart over some beers and I explained to him why that would never, ever, happen, especially since they were married. After that, he confided that this wasn't the reason for the split, though he did wonder about it for a long while.
The above won't necessarily convince anyone that I have an extra guardrails around physical adultery, though I hope it does evidence that I don't just simply think I'm immune to it because of my adolescent experiences. On the contrary, it heightens my awareness, sharpens my perception, and reminds me to never let my guard down. I am not certain I've ever recounted the two stories above to more than a couple of people, so it is sort of cathartic to simply recount them in a public forum for anyone to stumble upon. I'm trying to become more open, judiciously. I've been an introvert with innate suspicion of others' motives my whole life but I think it's time to relax that a bit while still staying frosty.
May God have mercy on all of us for our past transgressions as we look to Him and His promises realized through Christ. Be blessed.