So, I just don’t know how to wrap my mind around this. He states he loves me and is obsessed with me, then when the military makes us go long distance, I catch him on all sorts of dating sites. (Yes, I’m on here, but only specifically for friends and to meet people since I’m new to the area.) He once said that he loves me and is attracted to me, but that our conversation gets bland and he wants excitement. He even countered that we could open our marriage up?!? Man, I guess I’m here to just vent cause I wouldn’t mind having another man/woman to treat me well, especially when he doesn’t… but the thought of him with another just makes my blood boil.

Seems to me that your husband wants action on the side. Doesn't sound like he loves you enough to stay off various dating sites.

Sounds familiar

It's a dead relationship. You either find a way to create a new relationship with him (which involves being okay with secrets, lies and other women) or you end it with each other well and find someone who treats you like you deserve.

Love and play are different things. He loves you but he wants to play. When he was close to you how much did he love to play with you. How long will it take before he lifts you up..look straight in your eyes..or do more with you. If he is that kind of a man just know he loves to play and understand him. He might no be even getting ontop but he just want to brush lonileness away.

Are you always there to talk to him whenever he wants to. Maybe just check what have changed about you which you need to go back and be

Sounds like he isn't truly happy within himself. Until he sorts that I doubt anything will change. Clearly he's okay with the current situation as he gets and does what he wants.
The only one hurt here is you.
So it's up to you to decide what to do about it: stay or leave. Which boils down to: Do you love and respect yourself enough to know and truly feel that you are worthy of something better?
If not you likely will let him treat you like this, take you for granted, hurt you etc. for years on end, or the rest of your life.
The choice is yours.

He's not ready for marriage, he should be single.