I am looking for a movie starring Betty Davis. In this movie, she and the man she is married to never want to be without one another. They are an old couple. They go into the garage, turn their vehicle on, and lay in one another's arms as they are being gassed so they can die together. I think the title of it has the word love in it. This is an old movie.

Where Love Has Gone (1964) - IMDb

This is the only one I could find that might apply, but I'm not familiar with this movie.

You can search IMdB for Bette Davis and find all her films.