If you're truly unhappy, then leaving will make you unhappy also, but not forever. Sometimes, people don't want to change, no matter how you yourself feel about a situation or issue. That's just who they are and you can feel like you're not enough. I don't see him wanting to get married anytime soon; some dive into marriage carefree and excited, live life everyday yet some want to be strict about it and set up rules, set a clock that just will tick forever. You can stay and put up with him, and forget the future plans you shared initially together, which would mean giving up on your dreams which may hurt you more in the long run, or start doing you, and doing what you want in life. What's going to make you happy? You've only got one life: there's no point living it in misery or putting things off for another day a million years from now. I don't know if you'll ever see eye to eye on these issues, but it's hurting you that he can't change. I think you should find someone who loves you enough to change for you, even in the slightest, but Matt seems lazy, rude and ultimately draining.

Set yourself free and get out there, and find someone who wants to get out there with you. Someone who will care for you, look after you in equal measure, where things aren't based on a scale, a clock, or a time when things might be right; they could never be right and then those years you waited were wasted waiting for now. Someone who wants to work towards a future with you now, and not in the future when things may or may not 'fit together'. Life isn't a jigsaw that you have to fit together before you take action (within reason); live carefree, and if something that was perfect now falls apart in the future? Who cares. Letting go of love will be exceptionally hard, but you seem to just want someone to work with you and not against you, to commit to you. It's understandable that you're jealous, and the plans that you two had are slowly fading away. I guess you could make a list of reasons to stay, and reasons to leave. Breaking up sucks and it hurts, but you won't hurt forever.