Hi FL and congratulations on 15 days sober.
Unfortunately, we cannot do anything to change the past but can pave our way so we don't have actions which caused our regrets in the future.
I had a lot of regrets, it ended up in my husband leaving, he had got to the end of his tether with me. That became my day one, we reconciled but it is going to take time to build up the trust we used to have.
I was helped a lot by posting on SR and reading others experiences here.