Is my instinct right?

My husband and I have a friend that is single and does not want to really be in a relationship. However on a recent group trip to Cuba we had a couple situations arise and nwo I am not sure what to do. There were a lot of couples that went with us and a couple single guys. There were some moments during the trip where it was almost like he was trying to live through other peoples relationships, I thought it was weird but then just figures that he was scared of commitment. Then one day we were all laying at the beach and I got this feeling like I was being watched, I turned around and the "guy" was just putting his camera down. I felt lke he had been taking pictures of me or something. The next night my sister in law came yo me and told me that the other day she had felt like someone was watching her and when she would turn around this "guy" would be putting down his camera...two toher girls also came up to me on the trip and let me know the same thing...So I told my husband about it. This guys is one of his good friends and it was hard to bring it up...plus I had no proof. My husband confronted this guys and he denied the whole thing! said he would never do something like that and made a big deqal about him even being accused...Hoever that feeling remains and now I am not sure whow to handle this guy anymore...Opinions on this situation??