Anxious about commitment but anxious about being alone?

Hey, I'm trying to get help for my problems with my relationships. I was married for 4 years and it was an emotionally abusive relationship than ended when he had an affair with my best female friend. I don't know if this was the cause of my commitment issues, but since then I've had difficulties committing in a relationship and it has gotten progressively worse.

I used to be able to stay in a relationship until talks of marriage started, and then I would bail. But now I can barely start a relationship before getting freaked and sabotaging the relationship or running.

The solution I assume is to not be in a relationship. But when I'm alone, I have a lot of anxiety. I don't really have family I can rely on for emotional support and the few friends I have are all "surface level" friends who I wouldn't talk to about emotional problems. So I rely on my romantic partners to supply me with all my emotional support and when it ends due to my commitment phobia I feel crippling loneliness.

So what do I do? How can I be less anxious about being alone? Why am I so anxious about commitment? I want a healthy relationship but I don't want to be in one just to not be alone. As a side note, I am taking medication for my anxiety and I am in therapy, but the therapy hasn't really helpfully addressed my concerns. Any help is appreciated.