How do you all cope after being cheated on?

I'm struggling a lot right now and honestly just need to hear from someone who’ve been through this.

My ex and I were together for 5 years. I recently found out she was already seeing someone else before breaking up with me and she left me for him.

Since then I’ve been feeling really ugly, unwanted, and just bad about myself. I keep comparing myself and it’s affecting my self-esteem badly. Everything is falling apart.

I can’t focus on my work or anywhere else at all. I feel lonely, heavy, and not like myself.

How did you deal with the loneliness and rebuild your confidence after something like this? How did you start feeling “normal” again?