The warning signs of Jeff's infidelity were probably seen at the very beginning of his marriage.
Atheists do not have any real belief systems, so how can they take any marriage vows? How can they be faithful?
Catholic women who marry atheists are taking a serious risk as their unbelieving husbands may try to convert their wives and/or separate them from their families. In addition, since it is the faith of the husband which determines the faith the children will adopt, it is extremely important that a Catholic woman chooses a Catholic man. The husband is to lead the family spiritually. If the husband does not have the faith, how can he impart the Faith to his children?
If Jeff's wife married him for the money he could generate due to family wealth, then she is not to be pitied. That is called greed.
If Jeff's wife married him with the thought of converting him, that usually does not work.
Personally, I only became engaged to my future husband who was Protestant once he indicated that he sincerely wanted to join the Catholic Church and be baptized by her. He was baptized a month before our marriage.
Marrying an unbeliever such as a Muslim man is fraught with dangers as he will become radicalized if the wife becomes pregnant with his child.
I have known Christian men who have married Jewish women. Rarely will the Jewish lady convert to Christianity. Instead, the Jewish family will hound the man to denounce Christ and convert to Judaism, threatening disinheritance, until he ultimately does. It is an ugly scene. If a Jewish man marries a Christian lady, she will be expected to denounce Christ. Apostasy kills the soul.