A miracle happened when you became born again. You were recreated. You old sinful spirit was replaced with a new spirit. With your old spirit went your old sinful nature. You were recreated with the righteous nature of God.
Your new spirit came with the in-built capacity to love. Previously envy, jealousy, malice, strife, etc. were so common and easy. Now as a new creation the God-kind of love should be the default. The problem is many believers still identify with their old nature and have not completely dissociated from it. You may be wondering why is it that I still do the things I did before which are inconsistent with the God-kind of love?
You see even though your spirit was recreated, your soul and body remained the same. Your soul is made up of your mind, will and intellect. So you will have to consciously work on the renewal of your mind by the Word of God - Rom 12:2 - with the help of the Holy Spirit. And then you will have to bring your body under subjection to God's system again by the help of the Holy Spirit. As you continue to do the things described in this paragraph your love walk becomes stronger and stronger, and your capacity to love is increased.
Welcome to a life initiated and established by love. Have an exceptional day!