Officially ended my 7 year relationship

I’ve officially ended my relationship with my sons father after constant cheating and lies why does this hurt so much? We didn’t spend time together for the holidays and after seeing him go back to the same girl we argued constantly about I’ve decided to officially end things, he of course doesn’t care and has told me he’s fallen out of love. I don’t deserve this I did so much for this man, and I want to start my year off fresh please someone I need someone to lighten me up what a great start of the year 😪😪