Parenting

Hi Mama's need your thoughts and advice on a issue which i am facing. I have a 2 year old he is very shy and calm natured, when he is out playing with kids if any kids takes his toy he doesn't stop or defend it, he just gives away and will come back to us crying and will throw tantrum and if we are not around him he just steps back,this behavior makes me feel very worried wanted to know how to teach him to fight for his things by himself or just try to ask for or try to get his things by himself. Please share your thoughts and no judgments Thank you.