if you fall in love with another girl does that mean you didnt love your ex girl

I agree. If you keep on talking about your ex this and your ex that, then of course any girlfriend would think that you only love her because you were dumped by your ex. Stop talking about your ex girlfriend. Show your new girlfriend that you love her. I used to have this type of feeling before. I kept on thinking that my partner did love the others before me more. But he did his best to show me that my thoughts were wrong. He did so by little acts of love. Like telling me my firsts. Examples would be: first to watch weird movie, first to call him this or that, first to be the sweetest, etc. just think of anything that you have never experienced with your ex that you are experiencing with her now. He often told me I'm the first ever girlfriend who he can really talk to about anything. It's these things that made me feel he sees my worth. That's why my jealousy and insecurity disappeared. It takes time. If you love her, then show her, and understand her more. In the same way, be open to her, plus be honest with yourself because maybe you still are in love with your ex. Good luck! =)