AIO when my girlfriends ex lays in our bed?

My girlfriend and her ex have a child (3year old great boy). We live together 90% of the time , the other 10% i’m in my own appartement nearby my work . We have a 1.5y relationship. Now her son is sick, and hé wants both parents near him. I understand this, and during work hours i dont care, but I cant accept them laying in our bed together. She says its for the child, and i get that , but the Ex is laying in our bed... I just cant handle this image - I have a very hard time dealing with this - am I overreacting?