I don’t know that time heals all wounds, but it does soften the pain.
When you lose someone who was a large part of your life, the grief you experience is deep and intense. You are immersed in the feeling and you can’t rationalize yourself out of it. You’re better off absorbing the grief and letting the fire burn itself out before you try to make any future decisions. Just be for now. Later, the grief and loneliness and recrimination will subside and you can once more look forward to what lies ahead.
I remember a portion of a poem that I read long ago - "Better by far that you should forget and smile than remember and be sad".
Life goes on and we have great memories of good times and we soon forget sad moments and regrets.