What movie is this? Watched on amazon prime years ago

I watched this movie years ago and I’m trying to find it. Its based off of an older time period. It’s a romance. It’s about a couple who got married and the wife of the man was cheating on him. The man she was cheating on him with was sleeping around with other woman. He was also married. He promised he’d leave his wife for her but obviously never did. She told her husband. Her husband was going to leave her but didn’t. He took her on his business trip which was helping sick ppl out in the middle of no where. She ended up finding out she was pregnant with the other mans baby. She fell in love with her husband only to find he got sick with the illness he was helping other people over come. He ended up dying.