I'm in a bad relationship and I know it but won't leave
Is there something about it that has caused it to be bad?
Yes, it's boring and depressing to be in a long-term relationship
If you feel like the relationship is boring, you should leave. It will hurt you both a lot less to end it sooner than later.
I'm scared to leave.
I know it can be scary when something like this happens. It is okay for you to end a relationship if it's not going well. You need to communicate with your partner and tell them how you feel.