When I was 18, I had an affair with a married woman with a baby son, she was three years older. At first it was the most intense emotional and sexual thing I had ever experienced. I became convinced she was 'the one' and gave up college to get a job to be able to support her. I thought that was what she wanted. I never actually asked her...
After a few months, it became plain that she was not the person I imagined and vice versa. That was not her fault, she did not deceive me, I just filtered my view of her to fit in with what I wanted her to be.
She finally dumped me that winter, telling me she was being 'cruel to be kind'. I have come to realize over the years that she was totally right to do so and was much more mature than I.

It sounds possible that your lover is gradually cooling off and creating distance between you, and that may be the beginning of the end of your relationship.

I can understand how you have become so attached to her and how hurt you must be at her change of heart. It can be hard to believe at such times, but you will find someone else. The stage you are in now may hurt terribly, but it will pass and you will move on and learn to love again - maybe with someone who can build with you a family of your own.
I wish you well.