Do people usually still stay stuck on their crush after moving on?

This guy, his girlfriend, and the girl he use to has a crush on, work at the same place. The “ex crush” is still friends with the guy’s girlfriend and he doesn’t really care for them to remain as friends. He use to profess his love to the “ex crush” in front of everyone, including his now girlfriend. The girlfriend had acknowledge out loud that she knew he loved her the “ex crush”, at the time he would say it. The “ex crush” and the guy never seemed serious. He didn’t really ask her out, she never really seem to have taken him seriously. It was hard to tell if he was for real. But he told her “I love you” everytime he saw her at work. He kept calling her name when he saw her, and everyone noticed. Then suddenly one day, he announced that he and the friend of his “ex crush” were offically a couple. One night at work, he was overheard asking his “ex crush” to go into the back of the kitchen with him. She never went. He may have been joking. Its hard to tell. For a while up to this point, they act weird around the “ex crush”, as if they cheated on her. But there was no relationship. Most of the uncomfortable behavior is coming from him. He treats the “ex crush” like she is the plague. He gets uncomfortable around her, acts irritable, runs the opposite direction if he sees her, criticize her if she does something wrong (work related), and uses his hand to block his view of her if she walks near by. He does not like that his girlfriend and his “ex crush” still gets along. She does not seem bothered by them. He seems very happy and acts like a better person with his girlfriend. However, his mood changes when his “ex crush” is around. He use to talk about her not wanting his love, etc. Its been over a year since he started dating his girlfriend. Is it not enough time for him to get over it?