It's My Turn (1980) on Netflix

Chicago-based college mathematics professor Kate Gunzinger is at a complicated stage of her life. She has just moved in with her boyfriend, Homer, a builder, the move more out of a sense of "why not" than a compelling reason to do so. Their relationship is based on giving the other a total sense of freedom, which includes not being emotionally invested in the other's life. She has an interview for a job in New York City, which is more administrative than research, the balance which she could tolerate more than prefer. If she gets offered the job, she will not truly consider Homer in whether to accept it or not. Her widowed father Jacob is getting remarried in New York City at the same time as her interview, although she isn't sure if she will attend the wedding regardless since she doesn't like Emma, her new stepmother to be. At the last minute, Kate decides to attend the wedding. There, she not only gets a better sense of Emma not only as a woman but as her father's new wife, but also meets Emma's son, ex-Cleveland Indian Ben Lewin, who had to quit the game due to injuries. Despite Ben having a wife and daughter back home in Akron, the two embark on a more than casual relationship. Her short time with Ben that weekend gives Kate a better perspective on what is missing in her life, regardless of if there is a long term future for the two of them.