Husband wants to start using condoms

I know I'm overthinking because I get the reason he wants to start but tell me if it's weird. Me and my husband don't really know if we will ever want kids. Right now we DON'T! Neither of us like kids. Maybe we will change our mind. Maybe not. We use the pullout method with fertility awareness as birth control. My husband recently became a substitute teacher to bring in some extra money while he's in school. He mainly had been subbing for this specific senior class but went to sub for a 4th grade class and came home with condoms. I asked why and he said "Yeah. So children.... Are terrible." He wants to start using condoms now to make extra sure. Which makes sense but my brain is saying "Seniors are still kids/minors. Why is he all of a sudden wanting to take extra precautions now?" "Is there someone else?" I know it sounds stupid. I just need to hear I'm being stupid or if I should worry