Welcome to one of the best places to be during the most tumultuous time in your life.
Take a deep breath.. exhale and do it a few more times. Getting oxygen rich blood cells to your brain does wonders for your thought process.
You have no control over your spouse, only your own actions. His radical emtional swings based on taking the meds or their absence makes it difficult to work on a solid foundation. Him moving out of his parents house is good. Having the tattoo removed sounds like a statement.
People are there for you. Learning to ask for help is what is hard, at least I know it was for me. Look up Divorce Care, Divorce Support groups in your area. You aren't alone.
It sounds like you're proactive in taking care of yourself and your children. Children model after their parents. If you move forward in a positive way, so will they.
Don't worry about fixing him. Work on yourself first and the rest will follow.