Correct me if I am wrong, but it sounds to me like you have already made your decision. You just want us to assure you that, yes - end the relationship, despite the sorrow factor, and yes, there really are guys out there who want to commit and would love to have children.
Age 36 is a fine age, but as you seem to be aware, you are bordering on the end of childbearing years. Do you do it yourself (sperm bank), or hope to find someone who will be there from inception until death do you part?
Ending this relationship is a given. He doesn’t want what you want, and while you are still civil with each other, this is a good time to part friends. Who knows, you might get back together at a different stage of your life, depending on how things go.
Finding the knight in shining armor who will whisk you away to a new family and a house with a white picket fence?
That is up to you. A nice 50 year old guy with a stable life and career? A hot young 23 year old who makes you feel young again? Are you living in an area that has opportunities to meet both types of guys? Are you able to go out there and take the time and make the effort to meet them?
But my real advice is this; is this what you really want, or is this what you think you want? You are not the first 36 year old who has the dreams of a 20 year old…but considering you seem to have done very well with having one child, and seem to have been happy up to now with your living arrangement, are you really ready to commit to a lifestyle that, to be honest, is foreign to you?
Not everybody is cut out for the Leave It To Beaver, Ward Family way of life. It sure does look pretty from the outside, but sometimes the worst thing to ever happen in life is to get your wish.