Is my boyfriend cheating or am I over thinking

I’ve been with my boyfriend for over 5 years now, Valentine’s Day just passed and I can’t brush off my mind what my boyfriend said. We always talk about getting married, eventually I mean hopefully this year. I’m always kidding around with him and ask him when is he was going to propose. The week before Valentine’s he was being super kind and affectionate not like him at all. And genuinely thought he was planning on proposing on Valentine’s Day. While I was getting ready for dinner he was playing the game with his friends and said “Are you guys coming to my wedding”, I looked at him and then he corrected himself and said “Are you guys going to Japan?” I was a little bit too excited and thought it was finally the day. He didn’t, lol. Later on, I asked him if he was planning to propose this year and he told me he still hasn’t thought of it. Am I being oblivious to the situation or am I just overthinking it?