What should you do if your boyfriend of 1.5 years has a co-worker after him and he seems interested in her but he told you it was nothing and always treats you very well?
You should trust him and let him know that you feel
uncomfortable and together go to this coworker and state your
relationship loudly. In other words get her to understand you have
a solid relationship and she isn't going to shake that up. He
should have already cooled here jets by letting her know he is
taken and happy.