Girlfriend of 5 years let me and this happened, don't know what to do.?

If she can do that to you then she truly doesn't love you like you love her. If after 5 years she can do that then perhaps she was never the one for you. If she comes back to you after it not working out with this guy then what is stopping her from doing it again. You should move on and start looking for your true soulmate.