Blood after sex😳😳😳

Okay so I started my period Monday and ended like on Thursday . So me and my hubby decided to do it last night and it was great and everything then when he pulled out he saw blood in his dick .. And I went to the restroom to wipe myself and yup there was light blood , kinda like water with blood . He was saying it's his cum mixed with some left over blood but idk .. Has this happened to anyone ?