We all get jealous from time to time in our romantic relationships. It's only human, I suppose, and a bit of jealousy every now and then shouldn't be a problem; some people even believe that when you're jealous of someone spending time with your partner, it means that your feelings for him or her haven't faded.
But when jealousy involves severe and persistent fear and insecurity, it can destroy your relationship. This kind of jealousy is dangerous and powerful because it gnaws at you consistently, day and night, eating into your peace of mind, your time, and your ability to think about other things. It's a self-inflicted disease that, very often, has no basis in fact. And, as is most often the case, this kind of jealousy is ironically the very thing that eventually drives your partner away.
If you're worried about being replaced by somebody else, you probably suffer from some degree of low self-esteem. You don't have confidence in your own value and attractiveness and are constantly besieged by thoughts of someone usurping your position. Negative self-image can lead to self-defeating behaviours. It can cause people to act desperately and irrationally. It can end up controlling your life and straining your relationship.
Since jealousy has its root in low self-esteem, the first thing you have to do is work on your self-worth. Your feelings of inferiority probably stem from past experiences that conditioned you over time to believe consciously or subconsciously that you don't deserve happiness, love or success. Thinking that someone better and more attractive will eventually "steal" your partner is caused by the feeling that you don't deserve love; that you will ultimately lose in the romantic stakes.
Get the past out of the way. Seriously, stop believing in cliches like "history repeats itself". It need not. You have a choice. You can look forward to a better future, or keep imagining the worst.
Next, get in touch with and embrace your own uniqueness. That's what your partner fell in love with. That's what nobody else has. Re-connect with your authentic self and let it shine through. Don't get into the habit of comparing yourself with others or competing with others. When you aim to be like other people, you lose your own individuality. Your personality comes from your uniqueness. Find out what's missing in your life, and pursue it.
You will find that the more confident and secure you are about your place in the relationship, the more important and attractive you'll be to your partner. Insecurity and jealousy are very unsightly features on any person.
