The Affair (1971)

Chris Bradley is a young man who returns to his home city of Pittsburgh after several years of drifting and working odd jobs around the country since his discharge from the U.S. Army. Not wanting to move back in with his father and return to the family busies of manufacturing baby food, Chris meets and shacks up with Lynn, an older woman who works as a model in local TV commercials and becomes his 'sugar mama,' supporting him financially and emotionally. This begins to put a strain on the affair, especially when Lynn finds out that she's pregnant and does not feel that Chris would make a responsible father or husband.