The Chateau explains why showing how much you care
when a rival expresses interest in your woman is a problem:
Here’s where it gets interesting for philosophers and warriors of Game alike: While mate guarding may offer some temporary or discrete relationship security, multiple acts of mate guarding will paradoxically increase longer term relationship fragility. The mechanism by which this LTR instability is generated is a status feedback loop; if a man mate guards, his woman will subconsciously evaluate his romantic worth downward because (her sensitive idware will reason) only a beta male would feel the need to mate guard. An alpha male would not; his aloofness would be perceived as proof of his impenetrable high status.
Yes, when a beta male mate guards, his girlfriend will proclaim in the moment her ego-stroked thrill at his display of jealousy, but over time the accretion of those displays will erode her charitable judgment of his mate value. This is why women are viscerally disgusted by the thought of overly “possessive” boyfriends.
At the end of the day, people will do what they decide to do. There is no controlling them; the failure of one totalitarian government after another has shown that not even the threat of lethal force will suffice. The only reliable "mate-guarding" tactic is to do absolutely nothing at all, except to be sufficiently desirable that it is eminently clear that you can find a new mate whenever you wish.