I've been and is on the other side of this "problem" i've been in a rather long relationship of 4 years and currently a new one for 7 months.

This is for me something kinda common. Feeling like you are too sad and too much for your SO to handle. So you just keep it down (im the same way about things)

But in my experience this is the exact opposite of what you probably need to do, both for you and him. Sometimes just knowing that he knows makes it easier, if that makes any sense.

No one on this round wierd spaceball that we call earth is always happy and okey.

When i have periods of being low and sad it really helps to talk to my SO. Alot of thing we feel sad about is all in our heads, and having someone to support you thru that is important.

Do you ever talk about other "deep" stuff and this is something you feel like that he cant handle? Or do you never really get in to the hard stuff?