Distant? Anyways, you could always tell him how he "could" handle you. He isn't trying to ignore your moods, seems to want to help you. As someone with many issues, it's better to tell them how they can help you.
But if you really want to leave, then you do what you want. Don't worry about him, worry for yourself. Just make sure you end it with no regrets.
Say what you mean to say, what you need to say, then leave. Make sure he understands it's over. So that way both you and him can move on peacefully. Don't leave feeling bitter or you will regret it.

You have to figure out what you need and not what two different guys need.
The part where you can't tell the one how you feel, because he doesn't understand is a big deal. You need someone you can lean on. Even though we try to ignore our depression by helping others, you'll fall further behind in yourself. Take care of you and love will step in where it should.
Best of luck and hugs 🤗

Keep the guy you’ve got. You should know that dealing with depression is a lonely business and no one can really help, only time willl allow the mood to pass. Sounds like you have a good man. 🤗

Focus on yourself. If your current boyfriend doesn't know how to help find someone who will confide with you

Depression is hard to understand. Keep him, he sounds amazing