Walked out to the backyard and froze: my own boyfriend has my smoking hot stepmom bent over the hot tub edge, pounding her MILF pussy raw from behind while the bubbles hide nothing. She's moaning "harder baby" louder than with my dad, tits bouncing as he grips her hips and slams deeper, both too lost in lust to notice me. This cheating bastard is stretching stepmommy's hole with my dick, about to pump her full of the cum that should be mine. Total fucking betrayal and I'm soaked watching.