My boss is a little lot flirty?

I am not asking "what should I do" or "should I get with him", I just merely want peoples opinions on what is actually going on in this situation. So I work retail as middle management. I love my job and everyone I work with. My immediate supervisor is great, he works hard, and he inspires me to do the same. I am able to go to him without any issue if I am ever having any problems, and he and I are constantly joking back and forth and sometimes about inappropriate things for the work environment. (for example, we were taking a bunch of different kinds of pickles off a pallet to stock to the shelves, and well, I am sure you can see where the conversation might head) Anywho, though the conversation can be pervish, I generally don't care. I grew up around guys, and within the last few years, I've heard and been part of my fair share of inappropriate conversations. To me it's harmless, lightens the mood, and makes the work area fun with people aren't constantly guarding their mouths for fear of offending someone. Back to my supervisor...he is a good guy. He is one of those guys that's really rough around the edges but actually a really nice guy. Sometimes he takes things a little too far, when he is overwhelmed it shows, but he is great to work with! Now a promotion just came up for a job at the same level as him and everyone is expecting me to get it. I went for the 2nd interview today and my supervisor along with a few others were leaving as I came in. I sat down with the manager who was interviewing me (which is one step above my supervisor) and my supervisor walked by, wished me luck and blew me a kiss. That was completely out of the blue and he did it in front of the manager which I thought was odd. After my interview, I went back to take care of some items in the back room and he was there with another supervisor. He asked me if I had blown them away with my interview like I blew him away in my interview for the position I am currently in that I got a few months back. He then turned to the other supervisor and told him that I was so good in my interview he wanted to propose to me on the spot and that he would have married me right there. He has done some other minor flirtatious things randomly in the few months we've been working together. Honestly, I am just wondering what is in his head. Where we work, there is a strict no relationship policy between a person and anyone who can have some sort of power over them. The other thing is, my boyfriend of 3 years also works there in another department and we are very open about being happily in a relationship. AND I am in my early 20's while he is in his mid 40's so there is a bit of an age gap. Oh, and one final detail. I am not sure if he is married or not. One of my co-workers told me that he was a lonely man on multiple occasions, and I know he's been through at least one divorce, but as of right now I could not tell you. He just started talking about his "wife" at one point and all the sweet things he does for her. In fact, he loves to talk about all the romantic ideas he has to treat her, and all the stuff he does for her. But like I said, my co-worker says otherwise. So ideas on why he acts like this? I'm thinking some of the following... -He's crazy -He thinks I'll have an affair with him -He just likes to flirt -He it trying to get fired and bring me down with him!