m18 first roadblock in first relationship

Basic Info We are both 18. First relationship for both of us and been going out for 2 weeks. We have been friends for months and coworkers.

Last date she was acting distant. We talked and she said she still has feeling for a guy(also coworker) she liked for two years. They have done nothing unlike us.( Me and her have done everything but sex)

She has told him before about her feelings. Nothing happend. They did go to prom together but he didn't want to hang out with her after. She said they were about to go out a while back but he got "sick" and nothing happend.

She wants to get over him but doesnt know how to. We are still together. She keeps saying he has never gave me a difinive answer.

TL;DR Girlfriend still likes a guy before me, she told him before about her feeling. nothing happend. she has trouble getting over him.