Here's an unpopular opinion.

Are you sure the affair was the reason for her suicide? It sounds like she was already severely depressed and detached from life, hence the "change of scenery" trip. Living all alone in your dead father's apartment would screw with anyone's head.

More info is needed on what her husband knows, i.e. why he mentioned Jasper's name, because that may or may not even be relevant to her suicide. I suspect it is not. In the context of a person who has just suffered the loss of her father, is displaying classic textbook symptoms of depression and withdrawal, and is left all alone in her dead father's apartment, a brief love affair seems almost besides the point.