Summers and Price were in Price's bedroom with their newborn, having a conversation when an agitated Summers asked, "Why do you have to make me so angry?" according to the criminal complaint.
He then took the baby away Price and placed her in a bassinet.
When Price tried to leave the room, Summers knocked her down and stabbed her in the neck, face, and head with a sharp object, according to the complaint.
Price's mother, Wendy Damiani, 44, was in the living room watching television during the attack and heard her daughter scream, according to police.
When she asked Summers what happened, police said, he replied, "I know I hurt her. I love her, but I can't stand her with anyone else. . . . I don't want to live."
Summers then pushed Damiani down and stabbed her multiple times in the chest and neck, according to the complaint. He then swallowed a number of pills and left the apartment, police said.
Price escaped through a bedroom window and went to a friend's apartment for help, according to police.
When officers arrived, they found Summers in the woods near the apartment complex. He was bleeding from cuts to his wrists and received medical treatment, police said.
Price and Damiani were treated at a hospital and released, Falls Township Detective Matthew Tomcho said Sunday.
Police said the Bucks County District Attorney's Office would review the case and that upgraded charges were possible.