Don't Touch That Yoga Ball

To trap Jiang Muchuan and make him willingly serve as a "blood bag" for her and her parents, Qiao Shanshan deceived Jiang Muchuan by faking a pregnancy and birth, forcing him to both earn money and act as a stay-at-home dad. Sympathetic to the supposed hardship of Qiao Shanshan giving birth, Jiang Muchuan worked tirelessly without complaint, only to accidentally discover that Qiao Shanshan was hiding her personal trainer inside a yoga ball to have an affair. Jiang Muchuan then learned that the child he had been working so hard to raise was not his own, and Qiao Shanshan’s so-called "postpartum recovery" was merely an excuse for infidelity. Consequently, he decisively set a trap and caught them in the act in public.

Synopsis from DramaGo.