I like the idea, but it's difficult for me to swallow the group selection pill. If everyone else in my tribe has this population control gene but me then I bene

I like the idea, but it's difficult for me to swallow the group selection pill. If everyone else in my tribe has this population control gene but me then I benefit greatly because I'll have many more children without the tribe becoming overpopulated. Eventually my gene out competes the communal gene and the entire tribe overpopulates and collapses. Why doesn't this happen more often? What mechanism exists to prevent me from having this mutation? If I have this mutation am I essentially a cancer on the tribe from which the tribe cannot recover? This doesn't seem like the dynamics we observe in nature.