Should I tell my ex girlfriend I love her one last time b4 she goes?

Yes, but only if you don't expect her to come back to you. Do it for closure to get it all off your chest. Maybe even to make her feel bad for hurting you or to know that you did everything you possibly could to get her back. Then move on. You really don't need to be with someone that has a "shady dating history" or someone who cheated on you.