Is my man having a mid life crisis?

The past few weeks I noticed my live-in boyfriend of 8 years is suddenly very interested in his appearance, exercising everyday, and eating Special K for breakfast. He loves for me to go stay at my parents house, and always makes the excuse that he can't come with me. He used to love staying out at my parents place, because they live in a beautiful home, next to a lake. Lots of stuff to do here. Lately, he's been wanting to be by himself. He told me today that he is very proud of me that I am starting to be more independent of him, and that he thinks I am doing great by staying out here, and not calling him all the time. WTF? He is always on Facebook too. I honestly do not think he is cheating on me though. BUT, I do think he tries to act like he is single. I have a feeling he is on some singles websites too. What should I do without sounding like I am being accusatory? Should I go behind his back and check his computer? He also defriended me on Facebook, but he says he doesn't know why I am not on his friends list anymore. I have asked him millions of times already if he would like to be single. He says no way. My mother thinks he wants his cake & eat it too. He needs me for certain things, like staying in the apartment, because it is in my name. His credit is bad, so the apartment is in my name, and all the bills too, like the electricity. Do you think he stays with me because of this? There is absolutely no passion in our relationship anymore. He doesn't kiss me, or snuggle with me anymore. He sleeps out in the living room on the futon every night, while I stay in the bedroom, reading books. We used to be hot for each other, but he is a cold fish now. I feel very depressed about it all. Should I just leave him? We live in a very fun city, but he is 47, and I am 37. He is always going swimming by himself at night at the local swimming hole too, which bothers me. He does invite me, but sometimes I don't feel like jumping into 67 degree water at 9 o'clock at night. He is acting like Mr. Activity, while he treats me like the old lady that is supposed to stay at home and not have any fun.