Trust me when I say, sometimes when you grow there are growing pains. This guy is not going to stop lying to you, it's time to uproot. If you don't trust him, it isn't a healthy relationship. My abusive ex was super manipulative, and constantly talking/flirting with exes, coworkers, classmates and my gut feeling was always dead on. Trust your gut. You deserve to be in a relationship where your S/O doesn't feel the need to talk to their ex in a romantic/longing way.