How to break up with someone

Example Breakup Text - Before it’s Serious

I tried calling instead of texting because you deserved better than a text, but I also didn’t want to wait any more time to go by. I hope you understand.
So I've been thinking a lot lately, and I feel like I should be totally honest and upfront with you.
I think you're wonderful and I enjoy spending time with you.
You check all the right boxes: handsome, sweet, loving, fun, employed! But I can’t get my heart to work the way it should. I don’t want to waste your time or hurt your feelings ever.
You deserve a girl who will worship you for the catch that you are, and I’m not that girl, unfortunately.
I never want to lead you on or waste your time because it makes me feel like a horrible person, and I recently started to feel that way, so I knew that something was not right.
Sorry for such a sudden text about this; I wasn't sure about what I should do until now.
I hope you find what you're looking for and continue to be a wonderful, awesome person.
I would definitely be open to remaining friends if you feel so inclined. If not, I understand, and thanks for bringing lots of smiles to my face and being such a sweet, loving person.

Listen, I’ve been thinking. You’re a WONDERFUL guy/girl, and you check all the boxes: you’re smart, funny, cute as a button, etc., but I don’t think I’m the girl/guy for you.
With my history, I am only now getting my shit back together, and I’m just really sensitive and all over the place. I think we both need and deserve someone who is emotionally stable. That’s why I’m releasing you from our date tomorrow. Please know that I like you a lot, and I’m definitely cheering you on and wishing you nothing but the very, very best! You deserve nothing less!!