why didnt eddie and margueritte talk to eachother after his birthday?

I think it was because she knew it was the last time that they would be together and she wanted to hold on to that memory.

I thought they were estranged from one another for a time due to the fact that on his birthday Eddie went to the race track with a friend. At this time Eddie and Marguerite were supposed to meet with someone to arrange an adoption of a child. They were saving money for that purpose. She didn't want Eddie spending his time and money at the race track so she decided to drive there to take him home. In the process she had an accident which resulted in a long hospital stay for her and also deprived them of the money needed to adopt a child. This lead to bitter feelings for a time.