I kissed my best friend

I have a boyfriend whom I love very much we have a great relationship we've been together for over two years. I have a best friend that I have known for about a year and a half but in this time she has proven to be the most loyal person ever. A few months ago she confessed to me she was in love with me and I told her we could still be friends but that I did not feel the same way for her

A few weeks ago we went out to it and she asked me if I would please kiss her and she has suffered so much in her life that I did kiss her and it made her very happy and I want to be able to make her happy and if she wanted another kiss I would do it for her however I don't want her to still have feelings for me I don't want to hurt her and i know she is still in love with me but I'm very confused on how to help her

I feel very guilty like I'm cheating on my boyfriend and like I'm hurting my best friend at the same time

No one knows she is lesbian and no one knows that I kissed her we are just best friends in the rest of our friends eyes

It's really hard for her and I don't want to see her hurt

Any help out here?