The romance in this kind of love arises here from the fact that the outside world is not allowed to experience anything of this love. The two people who make up the couple here are often in circumstances that make life stressful and in order to shape this current life they have to function. In other words, there is no time to live or not so much.
There are a range of ways to pull yourself out of this everyday life for a few moments and of that romantic love is one, other possibilities would be alcohol, drugs, hobbies, an immediate exit from the current life (which would mean a continuation of what was experienced follows).
Romantic love is a snapshot and lives from the moment, in these moments that happen in secrecy, the partners usually give themselves everything, everything that is beautiful and which gives new strength for everyday life. Here, physical union is just as pure as intensive conversations or something to eat together. The variations are certainly innumerable.
It is not said that this cannot also lead to a lasting bond. Most of the time, however, this bond dissolves at some point. Ethically and morally, this kind of love is often called “cheating” and is often branded reprehensible.
As with everything else, the question here is how the parties involved deal with it. Here, too, “thinking” is required.