How do I stop being toxic?

Basically I need to be a better person to save my relationship. I love him but I have struggled a lot lately and have not treated him well and he is not happy. I need and want to change for the better.

I swing from one extreme of being very loving and affectionate to the other way of being snappy and the way I phrase things being not great. I come across as defensive when I don’t mean to, and it sometimes comes across as unpleasant and demeaning.

I need to learn to think about how I say things and level myself out. I need to learn to better communicate consistently.