Romance is an idealized situation. This can occur in real life, usually between two people who have a physical and emotional relationship. Merriam-Webster refers to a romantic encounter as one "marked by an expression of love or affection." These encounters also occurs in dramas and comedies. However, on film the romantic relationships may be exaggerated and the overtures are obvious.
An overture is an introduction or first move toward change. In personal interactions, an overture might be the first move that changes a friendship to a more intimate relationship. However, these gestures don't stop once a couple becomes exclusive or even after they marry. A spouse may use an overture to reintroduce romance into the relationship and keep things fresh.
An example of a subtle romantic overture would be a man purchasing a woman a drink at a bar. Unfortunately, it is easy for a person to misread these gestures because the man is not making his intentions obvious. Some men purchase drinks for their female friends and do not hope that they will take the gesture as a sign of romantic intent.
An example of an obvious romantic overture would be a woman surprising her husband with an intimate weekend vacation. Another overture that could introduce romance to a relationship would be a man asking a woman out to dinner. While a dinner invitation could be an act of friendship, a request to spend time alone with a woman makes the man's intentions obviously romantic in nature.