She could make your life a true hell
It is not a sign of love
There is a common belief among men that being jealous is loving, and this could not be more wrong. Jealousy comes mainly from a lack of trust in a person.
Jealousy breeds insecurities. The human being tends to compare himself with others, and for some strange reason, in the vast majority of cases, he underestimates himself with respect to the other. Women are no exception. Your girl may feel inferior and sad if you constantly talk about how pretty a famous actress, co-worker or schoolmate is.
A woman who doesn't feel trust in her partner tends to behave possessively. She might start to overthink everything.
You would never enjoy a quiet outing again because she would pay attention all the time to the direction of your eyes, just to check if you are looking at others. And if you were, she would be really mad at you.
1-She will consider all your female friends as potential lovers
2-She'll want to check your phone
3-She'll control your calls
4-The fights will be constant and for silly reasons
These types of attitudes damage a relationship and don´t allow it to move forward, but they can be avoided or controlled by :
Make it clear to those other people who are romantically interested in you that you do not want anything with them. Be concise and definitive. If it doesn't work, stay away from them.
Show her off and talk about her with your friends. This will give her the place she deserves.
Never talk about your previous relationships with her, let alone the things you did with them.