I have a very simplistic theory about being in relationship with someone, informed by my history of several relationships many short term and some long term, and several dozen casual hookups.

When a girl is smiling at you, acting enamored with you, seeming into you, seduced by you, flirting, acting feminine and adorable… that is when it’s worth it to be continuously committed to her.

On the other hand, when she ‘flips’ and starts acting less feminine, less adorable and being fighty or just neutral, you are getting into a space with her that has diminished returns on your investment (of commitment).

To put it more bluntly; if you have tons of options as a guy, there’s an opportunity cost of being committed to one particular partner for too long. You have to miss out on your biological drive to spread seed around to different people. This is not a big deal if you have a girlfriend who is behaving very well, but if she’s giving neutral or even negative energy for too much time, it is becoming not worth it to hold yourself back from enjoying other girls.

TLDR: if your girlfriend is smiling and acting like she’s enamored with you, it’s worth staying committed. However, If you have many options, and your girlfriend is acting pissy, argumentative or even just neutral, it may not be worthwhile to be missing out on opportunities with other girls.