<human>: Hey reddit, I need some help. My boyfriend and I have been dating for about a year, and have lived together for 7 months or so. I'm 19 and he's 24. 

Today I was reading some of his song lyrics on our shared computer, when I came across a journal entry of sorts. I couldn't tell it was a journal entry until too late, because he often writes opinion papers and I assumed it was one of those. Instead what I found was a pretty long letter to himself about how messed up his mind it. He went on to describe how miserable he is and how he feels as if he has a darkness inside of himself he can't explain. He has never shown this side of himself other than maybe once or twice when he snapped at me, and apologized immediately afterwards. In the book he mentions these times, and others when he comes off as cranky. He says he feels bad because he doesn't feel like he can explain it to me. He's never shown any inclination of violence. I'm more of a wreck than he is, I've been diagnosed as bipolar and occasionally find myself yelling at him when he doesn't deserve it. And yet, in this journal entry, he refers to me as 'the only light that shines through my darkness'. 

He also mentions that he knows he should get help, but it is just another thing he doesn't have the energy for. I want to help him, and I want to encourage him to get help, but I have no idea how to approach the situation. Help!

Provide a brief overview of the text.
<bot>: my boyfriend is fighting some mental demons and doesn't know that I found out. I want to help him. How do I approach the situation?