You should try to make a serious effort to never wish something in the past was different. This will only bring regret. This is what repentance is all about. Ask for forgiveness and God allows you to leave all regret behind.Yes that is true, but of course that only applies to fornication. When you fornicate, the sensation disappears quickly, no emotions of closeness emerge, there is often shame, guilt of that "off" feeling, and to compensate for those, you rapidly re-orient yourself to getting a new "fix" as soon as possible.
When you're married and you have sex with your spouse, it is followed by pure satisfaction and closeness, and the pleasant sensation lingers with you for as long as a week. I believe that psychologists refer to it as an "afterglow".
Furthermore, while you may feel like having sex again very soon, the sensation will be relaxed and non-urgent because you know that the two of you will be around for all of your lives.
That difference easily illustrates why it is indeed God's plan for us to enjoy sex only within marriage and nowhere else.