Jealousy in a marriage at any age will effect a marriage. A person that is jealous (as long as their mate isn't baiting them by flirting with the other sex) is very insecure and needs counseling. People who are overly jealous are miserable within themselves and I've seen some guys (even girls) beat up another guy or girl over jealousy and often this action is not called for. Who would want to live in a marriage where they are constantly walking on egg shells or wondering when their mate is going to get jealous and pop off or start arguing with their mate! Time to communicate and resolve this matter.