Advice plz

Guy I'm seeing at the moment (we aren't boyfriend and girlfriend but we do tend to act like it - we don't get with other people) has been very down for the past 2 weeks. He has been sorta depressed and just basically has been moody and not very happy (he admits this). I'm not sure what to do because I really care about him and like him but I just wondering because I'm not his girlfriend (we've been seeing each other for 2 months but friends before) he's very apologetic about the whole situation but he doesn't want to see me as often (which really upsets me) because he doesn't want to take it out on me. Because he's been like this it has made me quite unhappy and sad (I don't want to tell him this cause it might make him worse). He has just been quite distant and admits it but I just don't know what to do because his unhappiness is making me unhappy.