How do you know it's time to divorce?

My husband and I have been going through a very rough time for the past couple months.

How do you know its time to divorce or if your marriage is just going through a hard time and is going to get better?

I have considered calling a divorce lawyer and actually filled out a request for a consultation. Part of me wants to fight for our marriage but part of me is so drained from everything and just wants to say I'm done.