Eamonn Clark, STL
We all know that romance is a risky venture.
What is the risk we are concerned with here? It is the subtle movement from mere romantic feelings into “curiosity” (wanting knowledge of something – in this case, a person – which is not helpful for you to have… like certain kinds of immodest glances and even discussion, which are then “annexed” to lust) into more impure thoughts and indeliberate desire, into morose delectation (often manifested in and aided by outward motions, as already described), then often even into fornication, many or even most times in an unnatural way (viz., in a way that ensures no offspring, which character aggravates the sin even further).
Looking at people who are attractive is obviously necessary for one who is in the market for love. Of course, looking longer or looking at more than is really necessary starts the downward trajectory we have described above. One must use some discipline and honesty in these matters, without being unnaturally cold or rigid, allowing for some authenticity of expressions of affection. (Certainly, voyeurism, looking at indecent images, etc., for the pleasure of satisfying curiosity is always at least a venial sin, and if one is deliberately purposing to take pleasure in the desire to “go all the way” by means of such looks, even without self-abuse, the words of Our Lord in Matthew 5:28 have been fulfilled – it is “adultery of the heart.” The satisfaction of curiosity which simply arouses desire as an effect is not necessarily mortal sin, except if one has the wherewithal to consider or at least has the time to consider and experience to know that this is indeed a proximate occasion to mortal sin, as it is for most people before they are middle-aged, then even such acts become mortal sins on account of the treatment of one’s soul with such recklessness.)
It is very difficult to be perfect in this regard during extended courtship. There will be small slips into sin, as the desire for propagating the human race is extremely strong on account of the good that it seeks, and it is also the most corrupted desire we have (which, says St. Thomas, is due to the fact that original sin is transmitted on account of generation). But the risk of a person foregoing marriage who doesn’t have the strength to do so is far worse than the risks involved with courtship, at least in the long-term. So, there is a risk, but a proportionate reward, for most. These risks do need to be taken seriously, with clear boundaries discussed honestly between a couple – not first date conversation material, but maybe 4th or 5th date…
TL;DR: It’s okay to expose oneself to risks of some sin in romancing to avoid habitual falls into unchastity in the long-term.
But if none of this is much of a challenge, then we reach the fifth and final principle…
If you can raise your mind, do that.