Why would he say that?

Well it seems like he has some closet issues that you really don't need to worry about, or get involved in. Unless if it starts affecting you. I mean everything right now seems to be still alright. Besides the fact that his apologizing way too much, if that was my bosses problem then I would work for no pay lol jk. I think you should go and ask him how life is going. I know your not suppose to get personal in the work field but who knows what might happen. I also think you should just be strait up and ask him why his being so apologetic. (And make sure his on the same page as you/ for men its easy to get th wrong impression from other women)