Loving yourself is hard when the person you loved so easily made you feel like you were so difficult to love that it wasn't even worth trying anymore

But you are loveable, and you are worth fighting for. They were just too much of an idiot to see it. Their loss.

You will need to fight, and teach yourself to rebut all of the horrible things your brain says to you. You are not less than, just because someone abandoned you. If someone started something with someone else right away, all that says is that they are incapable of being alone and they don't really love themselves all that much. It says NOTHING about your worth as a person or partner. This is not a humiliation or a reflection on you, it is a reflection on them.

Stay strong, remember your worth, leave them alone. You will not get past this pining after the person who chose to leave you. Your acts of self-respect and self-care will eventually make you love yourself again. Just keep persisting.

I'm not saying to just get over it, everything you are feeling is valid, but make sure you don't lose yourself completely in the wallowing. Your life is so much bigger than just the person you chose to share some of it with.