Klay Thompson has been accused of cheating … again, and this time there’s no defensive scheme a coach can draw up to help him.  Thompson, now with the Mavericks and a former four-time NBA champion with the Warriors, found himself at the center of a storm Saturday after musician Megan Thee Stallion, whom he has been in a relationship with since last summer, publicly accused him of cheating on her.   “Cheating, had me around your whole family playing house… got ‘cold feet’… now you don’t know if you can be ‘monogamous’????” she wrote on her Instagram Story, the words landing like punches. “I need a REAL break after this one.” Megan Thee Stallion claims “cheating” Klay Thompson said he doesn’t know if he “can be monogamous.” Megan Thee Stallion/Instagram It wasn’t just the accusation — which is not the first time Thompson has been accused of infidelity — it was the tone. She was fed up. It felt final.…