I guess it's just hard for y'all to understand being men and all but that time spent "compromising" with a dude you've been with for 4.5 years, she could be with someone that actually knows what he wants. It's easy for you guys to be like "oh just wait" but every time she goes to the doctor they give her the high risk pregnancy talk. They've been together for over 4 years living together for most of it yet he doesn't know if he wants to marry her or not, why waste her time? Him being indecisive could fukk up her life plans. Just let her go, don't make her think she has a chance.
I'm going on the information OP presented in the thread. I haven't seen him mention that she's gotten such high-risk pregnancy talks. All I have to go on, is that for the better part of five years, they have had a damn good relationship and she wants that ring, which is understandable. If that's the case, either they agree on everything or both sides have done their fair share of adapting to one another. The dude just said he stayed with her because he thought he would be ready to cuff her for life, and come to find out he wasn't. It might not have worked out that way, but his intention seemed in the right place.
Here's a thought: If time is of the essence for her (and from what I saw, she didn't ask him to knock her up, she just asked him to put a ring on it), then why would she give him a whole calendar year to think about it on top of the years they've already been together? Her clock is ticking away during those 365 days. That's a whole year she could have saved if she just broke it off from the jump. Instead, she threw the ball in his court instead of them sitting down and just talking it out. It's not right to waste somebody's time, but it's foolish to allow someone to be in the position to waste time you can't afford to lose.
And don't get me wrong, OP's girl is not wrong in how's she's thinking. I agree with the idea that OP should have known his intentions by now and if it's me, I wouldn't co-habitate with a girl I don't expect to wife. But I'm not him and I don't think like him on this issue.
If he's not ready to give her what she wants, he's gotta walk away. I'd hope they can find a way to work around it because good, strong relationships are hard to come by. But if they can't, they can't.