Why I have put up with this for so long?

I feel I'm frankly at the point where I am ready to file for divorce.  I feel like I've lost myself.  I think I've felt like that our whole relationship.  I am sick of feeling like I am his mother.  I am sick of my needs always coming last.  I am sick of feeling so alone.  I am sick of feeling unsupported and taken advantage of.  Most of all, I am sick of being lied to.  My husband has a porn addiction.  He is always on the brink of addiction with alcohol or anything else that will "numb the pain."  He hadn't been watching porn (at least to my knowledge) for a four months.  He started watching porn again and I found it on his phone.  He admitted to it and said it was a one time mistake.  I found crap on his ipod a week ago.  He tried gaslighting me and saying it was from before.  I told him I know it is not from before, because I have checked his ipod periodically.  He continued to lie even when confronted.  He continued to say I was crazy.  He then finally came clean.  I told him I am done with his lies.  I told him if he watches porn and isn't forthcoming enough to tell me about it, I'm going to the divorce attorney.  What do I find yet again on his phone.  He was home one day this week and nothing was done.  I knew that's what he was doing.  I'm tired of this cycle.  He says he's not going to confront any emotions or feelings, because that's what led to his depression.  How the hell can anything be accomplished if you ignore everything?  If you ignore your spouses emotional needs?  He is in serious denial.  I have never wanted a divorce.  I have stood by his side through so much.  Yet, where is his compassion?  Where is his motivation to be a good husband and father.  He says he tries.  Yes he does try, but it always comes back to his constant lies.  How can I ever trust someone who continues to lie and be dishonest.  And someone who has no empathy or compassion for what I go through?  His behavior is unacceptable.  I'm scare to leave my husband, but I am scare to stay.  I don't want to start over at this point in my life.  However, I don't feel I am really living either.  Thanks for letting me vent : )