My sister was in a similar relationship. Her relationship went on and off for almost 5 years!! They too lost a baby.
Eventually she DID marry him. It lasted about 6 weeks and ended in annulment .
She later told me she married him for all the wrong reasons. She was afraid to start over, afraid of being alone, felt that she had put so much time into thier relatioship it was expected of them to marry, they had had some wonderful times, and she thought it would get better once they were husband and wife. It didn't and won't. If anything, their relationship got worse. She was in love with the idea of how things used to be between them, if that makes sense.
Everyone's situation is different. However, you seem to know the right thing to do. Follow your heart. When one door shuts, another one will open! Prayers for you that your steps are guided to follow the path that has been laid for you to follow. The right thing to do may not always be easy, but what is waiting for you will be worth it.
