My husband's best friend is my good friend too and hangs out with me all the time. Is this ok?

My husband is currently deployed in Iraq. His best friend was deployed with him too, until the guy had a seizure and the doctors decided to send him back to the US. When he arrived I was the only person he knew, bec all his friends (inc. hubby) had just left for Iraq. My husband asked me to help him out for a while since all his things were still overseas and I obliged. We are also good friends and have been hanging out on a daily basis, we go to the gym to work out and then he comes over to watch tv. He has never tried to make a move on me and is always going out of his way to help me since he knows my husband is gone. The problem is, people are starting to talk and they are saying that he shouldn't be hanging around me every single day of the week of he wasn't interested in me. He talks about girls all the time and even told me that I am like a sister. But it's starting to bug my hubby. What should I do? I love my husband lots but still want to maintain the friendship.