how to get over someone...

I try really hard not to like someone if I know it won't go anywhere, but I ended up liking my trainer. He's such a gentleman. I'm nearly 40 and I've never been treated with kindness and care by a man before this. He was always professional, but I did catch him staring at me once when we were out at a group dinner. I play that moment over and over. I want to text him to say hi or something, since we don't work together anymore, but I keep stopping myself because I don't want to indulge these feelings. Crushes don't feel nice anymore at this age. They just hurt. How do I get this to go away?