Need opinions!

So I am currently across the country away from my husband for a total of 6 months for work (army). I am on month 4 of 6. Last week my husband told me he wouldn't care if I slept with someone else because "I have needs". What are your opinions on this? It's only made me think that he's already cheated on me and wants me to do the same to make things even. I told him this and he keeps denying it. He's had a history of talking to other females on social media so this only makes me think he's done it even more. I even tried to send him a sexy pic today and he never even mentioned it, just kept on talking about other things without even bringing it up. I feel like he is losing interest but I can't find out if he's cheating because I won't be home for a few more months. What do I do?