I am sorry that you are going through this, it is not nice at all. Not to mention the amount of people that then say you will be ok, there is a light at the end of the tunnel, can just hush up, even if true.
I went through my break up 10 years ago when my husband walked out leaving me with 4 kids under 4, the baby was 9 months, to be with an older woman with no commitments.
Break ups are fucked up and no amount of words of comfort will help you right now.Though I am still going to say be strong. It will take time, not going to lie, took me many many years, some people not as long.
Please just don't over think things and if you need to cry then cry and cry until you just can't anymore.
Take Care