In 5 years of relation with Lay, suho never Felt the latter treated him like his boyfriend... He knows Lay never love him the way Like how he wanted him too...
On other hand, Lay Just took advantage of him not knowing Bunny's Past truth...

 he stretched out his hand and gently touched his stomach.

    "Baby, see clearly, he is your daddy..."

    "Even though he is scumbag, but I still fall into a foolish situation..."

    "Your daddy will have a home with someone else in the future, Dad  don't want him anymore. Dad raises you alone, okay?"

    "Tonight is the last night our family of three lie together. Tomorrow gets up, you remember to say goodbye to daddy secretly..."