Been AFK for a while, but a social circle question...

One of my big problems is not running with my gut feeling on things. Well, right now my gut feeling is telling me to chase, and go all caveman. Problem being, the girl in my extended families' social circle, and has a BF. On one hand my gut says go for it, its there. On the other hand the social circle repercussions could be bad. I mean, I already know the answer, social circle disasters that could affect family relationships are to be avoided. Just needed to vent a bit. My gut doesn't normally speak quite this loudly.