If you value your relationship, you must actively manage your environment and mindset. 1. Limit One-on-One Time
There is no version of this story where pursuing the mother ends well. It is a "scorched earth" path. If the attraction is a dealbreaker for your desire for your girlfriend, the most "deep" and honorable thing you can do is exit the relationship—not to pursue the mother, but to allow your girlfriend to find someone who sees her as the standard, not the runner-up. If you value your relationship, you must actively
If you truly "cannot hold back," you have a responsibility to before you do something you will regret. She deserves to be with someone who is fully invested in her, and you need space to figure out what you truly want. It is a "scorched earth" path