My husband accused me and my stepson of having sex

I've been with my husband for 11 years. My stepson is 17 so I've been in his life since he was 6. He mainly lived with his mom, step dad, and half brother. They all passed away in a car accident a year ago so he lives with us. I have triplets with my husband who are 3. My husband and I have always had a steady marriage but he's been acting weird lately. Extra loving towards me and more angry towards my stepson. I heard them yelling because he was squeezing my stepsons ear and hear and my stepson was saying he's hurting him. My husband was yelling if he was fucking me and my stepson cried saying no and that he's a virgin and never had sex with anyone. My husband was starting to draw blood and I grabbed him to make him stop. He has been apologizing to me for scaring me. He just doesn't want to lose me. I'm uncomfortable how everything has been transpiring lately. And I'm having trouble looking at him the same.