There's nothing wrong with you in that way. It can sure be a very difficult thing to change something so drastic in your life even if you know it's for the best.
Best thing I would tell you is keep in mind that you're doing this because it's what's for the best. The relationship is harming you and it's not making him any better. You know this or you wouldn't be considering the break up. If you need more, call up someone who could help you like a friend. I hope this helps you.

You're afraid of change and the unknown because right now you're content with your situation because if you weren't you would have found the strength irregardless of any excuse that you've come up with. First and foremost you need to learn to love yourself enough to be brave enough to know that you deserve better. Why do you need him if you cheated? All he's doing is taking up space in your life at this point because you've been with someone else. He's a placeholder. Ask yourself do you need him?

i wish i could give u some. i have given u some of my best ideas

Just leave

Yeah tell him you cheated and maybe he will help you leave

Tell him you cheated on him. Done and done

Is he doing anything bad/mean to you?

U should leave him alone

What's stopping you?

Why did you cheat on him don’t you love him ?

Give him a proper closure

Tell him you cheated. That should end it

Yes
https://my.clevelandclinic.org/health/treatments/15993-testicular-prosthesis
They're not real balls, but ersatz testicles might help. YMMV.