An initial show of indifference to news that you've gained something in your life, such as a job or new home, or if you're talking to someone and your significant other suddenly becomes quiet and inattentive are signs of jealousy and envy.
When someone is jealous, one of their first attempts to defend against it is to pretend they don't feel it and they shut down in the moment. Someone who is not envious will ask questions about your news and be happy for you. A significant other who is not jealous will join your conversation with others. There will be no signs of indifference in those who are not jealous or envious.
Insults that are hurled either outright or defended as "just a joke" are often signs of jealousy.
Another way that people try to protect themselves from uncomfortable feelings of jealousy and/or envy is to convince themselves that they are better than you. They try to prove it by insulting you, your lifestyle and your significant others. They may also directly insult people who are important to you.
Snooping and Overly Curious
If your significant other is snooping through your email or phone book or other personal items, they may be jealous.
Chances are that they have a specific jealousy about you and another person and suspect lies or infidelity on your part. A jealous partner is often fearful and accusatory as well. They are insecure that they aren't enough for you because of their own fear of not being good enough. A friend who wants to know every minute detail about your life or a new acquisition, to the point of being rude and prying, is probably envious. This type of envy is fueled for a desire to compare themselves to you, again in an effort to feel that they are better.