I watched the movie when I was small. I assume it is late 80’s early 90’s. Seemed like it was a scary movie. The scene I remember is two adults having sex. The camera angle is through the crack of a door. There is another scene where the kid is running through the field. It seemed that because these two adults had sec, this resulted in the kid dying in the field. That’s all I can recall.
Maybe https://www.imdb.com/title/tt0087803/?ref_=nv_sr_srsg_0_tt_8_nm_0_q_1984
He watched his mother die in the field.