I understand the temptation but if you truly feel that having sex before marriage is wrong it shouldn’t matter if you are in the same room or not.
No, with respect, I don’t think you do understand the temptation, and underestimate the power of temptation in general.
One of the things that I can recall being taught to me in my Catechism classes (I know that dates me, because I actually went to school when Catechism was actually taught) is the prime importance of avoiding sin by avoiding the occasions of sin. If you gamble to excess, don’t go into casinos. If you can’t control your intake of alcohol once you start, don’t go into bars.
Where a man and a woman are attracted, and that attraction leads to the development of a close one-to-one relationship, sexual intimacy is much more the next expected stop on the route, rather than an optional detour. Even a biologist (like me) can make that case very easily, without reference to the spiritual reality of two becoming one flesh. We are made so that coming to that latter reality is a natural step, not an enforced, unnatural one. So avoiding that step is a fight against not only spiritual forces, but biological human nature itself. A couple is playing Russian roulette with 5 bullets in the chamber if they think they can fight that.
And suppose they succeed? Is that a victory? I am hard put to accept that the suppression of this mechanism, day after day, in the face of constant temptation, can do nothing but harm to the individuals involved.
It’s no more complicated than the admonition to leave the matches in the box on the shelf if you don’t intend to start a fire.