Self-esteem gone- is this normal?!

Hi everyone...first time posting grateful to find others that may understand.

My husband and I have been together ten years with ups and downs. As a whole for the first few years it was a fairy tale. We first met in sixth grade and had been friends on an off for years, finally getting together in our late 20's. He's kind, creative, gentle, basically an answer to prayer.


As soon as we got married a strange pattern emerged. He was diagnosed with ADD in kindergarten and has struggled all his life with depression, anxiety and constantly feeling inferior to basically everyone. I noticed that there were constant issues with other women. It's not so much that he was having affairs. I suppose it's totally possible but it was more that he never would draw a boundary with a woman. He would have private messages on social media and hide. I'd always find out and when reading the messages, it seemed pretty innocent but it was so disturbing that he had no sense of loyalty.


Lately it's been worse and worse. He is constantly talking to girls on social media, mostly instagram, and constantly lying about it. It hurts me so badly that he cannot be loyal, never mentions that he's married. I am so vulnerable with him and clear about how small it makes me feel, but it doesn't matter. Today was the last straw....theres been three just this week, but today on our cell bill I found pages and pages of texts to a co-worker that he was deleting. I packed a bag and am now at a friends. 


I'm really hurting so much right now. I love him so much but it feels hopeless. He says he doesn't understand why he does it and I'm struggling so hard with feeling so worthless. Does this happen often? Is he so desperate for affirmation that his integrity and marriage doesn't matter anymore?