Feelings for a co-worker

I’ve been in a job for 15 years now. Worked my way to the top. Last year we took on some new staff. One woman in particular caught my eye. We exchanged pleasantries in passing but nothing more. Very attractive lady. Thought nothing more than that at the time.

Slowly started to ‘fancy’ her. A month ago I found out I would be training her in her new role. Meaning working together every day. Pretty much since then I have developed feelings for her. I’m 32 and she is 44. Both of us in relationships. Its like being a kid at school again having a ‘crush’ so to say. I literally can't stop thinking about her all day everyday wether i’m at work or not and working with her is good as I get to spend time with her but also hard to keep a lid on my feelings for her and stay professional. I am at a bit of a cross roads, I don’t see me expressing my feelings to her anytime soon as I think she would just take it as a massive shock and it would probably cost me my job but at the same time it is driving me mad being in this predicament. Any advice?? TIA