Man its important to show emotions. When showing your vulnerable side you are stronger than when just trying to be strong.
I always show my emotions to girls and its not a deal breaker. I do it because I want to be understood and they understand me better by it.
I say be open and honest, dont hide or hold back anything. If it dont work then move on. You already tried to be strong so it didnt worked. Theres actually nothing you can do if she likes someone better. You can try hard but take only second place. I say - man find a girl to who you will be number one. It seems like now you are trying to desperatly hold on to this girl when she is just keeping you at hands distance. No real man would be okay with being backup player. Thats not the position from where you penetrate girls.
Doubt kills more dreams than failure ever will