Great advice from the guys above.
switch7 said:
ok, so once I finish it my head, do I finish over text or in person?
Just one point on this specifically:
You do it by text. BUT- and it's an important detail- you are not finishing it, you are informing her that it's finished.
I would go along the lines of:
Hi *name*, I hope you're good.
I've been thinking things over recently. Unfortunately I feel like this isn't working and I get the impression you feel the same. With this in mind I think it's best we call it a day. Thanks for some great times, and I wish you and *kids name* all the best. Take care.
*your name*
It's softer than what some of the guys might suggest but here's my reasoning:
"I've been thinking things over recently"- her cue to brace herself for the rest of the message. Shows it wasn't a rushed/emotional decision/reaction to her behavior. She may even doubt whether she was the one to begin this whole process.
"Unfortunately"- goddamnit you so wanted that glorious white wedding but fate wouldn't have it *shakes fist at sky* (it's the fault of circumstance not you)
"I feel"- a woman's way of thinking. Make her empathise with you. You can't help your feelings, right?
"I get the impression you may feel the same way." Call her out on her behavior and lay some blame at her door. Even if she doesn't feel that way she will be able to understand that she has given you that impression and it's turned you off.
"best WE call it a day"- you're both making this decision together.
Finish on a kind note as it'll avoid riling her and the subsequent drama.
You've laid some of the blame on 'fortune', some on her. You've been dignified. You've informed her of the decision with no option to negotiate. You then give her no more contact.
I've personally found this method to be really good for keeping women sweet enough that after some time you can grab a beer and bang them with no hard feelings.
(I do some copywriting work and am used to targeted, impactful language hence what my seem like over-thinking to some)