Regrets and remorse kill me

At the moment I feel infinitely guilty for not having done the maximum for my husband who is leaving me. I didn’t prove my love to him enough, I wasn’t sweet, loving, sensual, present enough, I missed a lot of things with him and now it’s too late. His love is gone and it’s my own fault. The consequences of my own actions are unbearable. I thought we were together for life, I took him for granted, I thought I was doing well enough but in reality I missed everything, and the thought that I’m responsible for my own pain (I love him, he’s the love of my life, my whole universe is collapsing) is unbearable. I would like to go back in the past and do so many things differently.
When I am drowning in this whirlwind of thoughts of regret and remorse and the feeling of having dug my own grave, I suffocate, I collapse, I can no longer live. I love him so much, and it’s too late, and it’s my fault.
I can’t use the tools of the scholars, I can’t think, I can’t get out of it.
Can you help me? I’m sorry.
Thank you xxx