Desklamp

Hello, One of my letter writers for PhD. program is my current undergraduate research advisor. They extended an invitation to graduate school but I told them that while I was interested, I would also like to apply elsewhere. This person told me they would support me as much as possible, but has also mentioned that his letter would say something to the effect of "They're good and I wish that they would stay here with me and do research". I don't know if I am being paranoid or not because I do believe this person would write me a very strong letter, but this seems like a conflict of interest to me. Can anyone else share their opinion on this matter? Am I being paranoid? Thanks.