Is he talking to other ppl

I been wit this older guy for 5 months we meet at work and the job is a warehouse. We are supposed to only talking to each other no one eles. My friend texted me saying that he came up to her and asked her does she often work up here and ask for her name and said that he was going talk to her later. She said that he walked by her again and didn’t say anything. This is not the first time someone telling me he been friendly wit females. This the second time I confronted him and he lied to me saying he never talked to any female there. What should I do should I move on? I don’t work there anymore more and now I don’t trust him