I am a firm believer in things like: all things happen for a reason, you are the chooser of your own happiness/destiny and not to live in the past.
The things you miss are not reality anymore. They were material, and a fantasy you struck up in your mind. It is not fair to compare current situations and people to those things you've lost, as nothing is perfect.
If you do not love this man, I would suggest breaking off the relationship, if he is a nice guy, all the more reason to do it quicker. Since you say you have lost your path in life, and your happiness it sounds like you need to go on a trip of self discovery and in order to do that, you must be alone. Find how comfortable it can be being alone and finding that company within yourself...
The hurt, anger, all of that will not go away until
you are ready to let it go. Everything that has happened in your life, molds you into the person you become. It is up to you what you will make of your lifes journey
it is never too late, until it is too late!
And one more thing, indecision on big steps like those are normal.
I have gone back and forth a million times with myself and my soon to be husband on the subject of having kids for many reasons.
It is a really big and sometimes scary if you allow yourself to over think it enough, change in your life. Be grateful it didn't happen in your previous situation. Now if and when it happens, you will be able to truly enjoy the experience rather than feel regret and anger towards yourself.
And marriage can only be appreciated when your heart is truly smiling. Things are moving along for you the right way, don't be discouraged! Everyones journey is different, do not place too much pressure or blame on yourself.