I know the feeling of staying largely because you know they will fall into a heap without you - I stayed too long in my previous marriage for the same reason. Thing is though, we shouldn't sacrifice our own happiness to make someone else happy. Her happiness, friendships and social life is up to her to take care of - it's not your responsibility. Yes, she may crash and burn if you leave, but you really need to put yourself first.
You say you love her very much. However, I'm wondering if you've ever given yourself permission to question your love for her. Thinking back to leaving my ex....I also used to say that I loved him very much. But the truth was that I had fallen out of love with him but hadn't acknowledged it to myself. Sometimes, acknowledging the fact that the love has gone can be one of the hardest things to do. It was the ease in which I moved on which proved to me that I truly didn't love him anymore.
At any rate, having a foul mood once a day would not be acceptable to most. I hope you realise that you deserve better.
For what it's worth, my ex did crash and burn when I left. But I soon met a wonderful man and we're still very happy together 20 years later. My ex is still in the same hole that he was in when I left. I feel sad for him, but I don't regret leaving for one moment. If anything, I regret not leaving sooner.
Never regret anything that has happened in your life. It cannot be changed, forgotten or undone. So, take it as a lesson learned and move on.