Because of the townhouse scene, I would say it’s definitely Stella Dallas. Barbara Stanwyck plays the mother who steps out of her daughters life in order to give her happiness.

Since you liked this movie, I would recommend another one with a similar storyline. “To Each His Own” (1946) with Olivia De’Havilland. It is one of my all time favorites, and I cry every time I watch it. She plays a woman who gives up her illegitimate child, a son. You can read more here:
http://www.imdb.com/title/tt0039040/