Well its hard to answer just like that... Have you had problems? Fighting more than usual/spending less time together? Did he say this randomly or where you in the middle of an argument?
My first thought is (but I can be completely wrong so don't get mad) is that you have been together for such a long time that you have become to "used" to each other. You have probably done the honeymoon-fase, the freshly in love-fase and had fights and makeups. Seen each other sick, without make up, and maybe puking your insides out. You know everything about each other, spend a lot, if not all, of your free time together. So in other words there are no more "surprises" for you (if you don't count marriage and kids) except for the ones you make up by your own. And sadly, a lot of relationships don't last longer than that if there is no spark to keep them going. I think it was in Scrubs they once said that the people in the relationships that really last goes trough the same sh*t that every one else, but the difference is that they don't let it take them down. And from the only comment you asked about that your boyfriend said, I would think that he has come to a point that he doesn't know if he wants to keep fighting for the two of you. It doesn't mean he don't love you or anything, I personally think that if you loved one once you'll love them for life, even if you brake up, then you'll only love them in a different way. But I also think that he is questioning if this is the way he wants to spend the rest of his life. Maybe he is having a bit of a crisis a lot of people have at the thought of settling down. We all have a lot of things that we wanted to do in life, experience, but we sometimes can't do them all.
Like I said, its only a guess (because ofc all people is very different, and maybe he isn't a person who thinks like this, but hey, you only gave us one comment to go on), but I would say that your boyfriend has come to the point (since you have been together for almost 2 years and is in the age of 36-45) where he has thought of taking your relationship a step further and the thought scares the sh*t out of him and reminds him of all the things he wanted to do (that he can't do as married) and all the things he won't be able to do. And the more he thinks about it, the more appealing he thinks other things is. And maybe he has a single friend who tells him about this awesome party he went to and hot girl he hocked up with?
the only thing I think you can do is talk to him. We don't have the answers, only he does. Don't argue, don't get defensive, don't accuse, just hear him out. If he says he is trying, then maybe there is something you can do together to lighten the spark again?
(and by the way, you shouldn't do all those things for him, its not the things you do in his house that matters. and he is a grown up man (hopefully) and can do those things for himself. And it makes you sound like his mother. But maybe I'm just an in-the-closet-feminist). Good Luck!