This dream appears to be rich in emotions and themes related to your relationship with your estranged wife, as well as feelings of comfort and concern. Here are some possible interpretations:

1. Reconnection and Nostalgia: The act of watching a movie together with your wife and child suggests a longing for closeness and a return to more harmonious times. This could signify your desire to reconnect with her or reminisce about shared experiences in the past.
2. Support and Encouragement: Your suggestion that she get a job doing something you are interested in indicates a willingness to support her and perhaps a hope for her success. This reflects a nurturing aspect of your personality and your desire for her happiness.
3. Intimacy and Vulnerability: When you hold her while she lies down, it symbolizes a moment of intimacy and trust. This could represent your yearning for physical closeness or emotional vulnerability that may be lacking in your current relationship dynamics.
4. Fear of Change: The moment you wake up as you reach for the doorknob suggests anxiety about confronting a new reality or change. The tightening of her belt might symbolize feelings of preparation or readiness for a new phase in life, which can be both exciting and intimidating.
5. Unresolved Issues: The presence of worry about what’s on the other side of the door may indicate unresolved feelings or fears about the future of your relationship. It suggests a hesitation to fully engage with potential changes or challenges that may arise.

Overall, this dream could be prompting you to reflect on your feelings regarding your estranged wife, your desire for connection, and your apprehensions about the future. Consider what steps you might take to address these feelings in your waking life, whether through communication, setting boundaries, or seeking closure.