Dating after 2 years

I’m not sure if every women has experienced this or something similar.

But my ex literally left me to be with another girl and her kid. Me and him have a 2 year old. I have never felt so ugly and just embarrassed. I always wondered why he left me and what did I do. He just simply says I don’t love you no more. After 5 years with someone he really just left us like that.

He would call me bitches or make fun of me to be with her it was crazy.

Now I just feel so lost on dating? Its been 2 years since I’ve been single.

Any advice?