affair?

My husband works with a woman I just don't have a good feeling about. Last month he was traveling with her and it was her birthday and they were doing shots and I just saw on his phone that he was texting her at 2 am telling her how awesome she is and how he would do anything to make sure she stayed happy so that she stayed in town. I confronted him and he swears that nothing is going on and he has no feelings for her. Am I being too paranoid