Crush on manager

I can't stop thinking about my manager. I'm in my late 20's and engaged to an amazing man. Our relationship is good. We've been together for nearly 4 years and have lived together for 3. We are planning on getting married in about 8 months time. I would be lying if I said it wasn't a little stale at times. We have sex 1-2 times a week, and have a little physical contact outside of that (pinching each other's behinds, a quick kiss at bed, tickling sometimes). He's very sweet, bringing home flowers, getting me treats, making dinner and doing chores when needed. He hits all the "check marks". But I sometimes feel like we don't have enough passion. Enter work. I've been at my current work place for 2 1/2 years. I'm a full time supervisor, newly promoted. My job is in retail.. hard work, little reward, and without good coworkers it wouldn't be worth doing. For as long as I can remember I've had a massive crush on my manager. At first I thought it was just a stupid physical attraction that would go away in a week or 2, a month or 2, a year or 2? But it hasn't. We are friendly towards one another, but not in a flirty way, although he makes a lot of dirty jokes. We talk quite frequently at work, about anything and everything, and because we are the same age we share a lot of the same experiences with music and school growing up. When we talk, he has this way of looking so intense, like he's really listening and absorbing everything I say. When I first started he had a girlfriend, but they have since broken up (which has made the crush even harder to manage). I try not to show my hand too much, I never really flirt or probe too much into his life.. I didn't even ask why him and his girlfriend broke up, even though I REALLY wanted to. I'm not the type of person to act unprofessional, which makes it worse to blush constantly while we're talking and do stupid little laughs at even the most unfunny jokes. I definitely don't think he has any interest in me, but sometimes I do wonder. We had a work get together some time ago and were singing karaoke. While some of my other coworkers sang together, he was going through a list of songs and I must've went "oh!" at one of them, because he invited me up to sing with him. He had no clue what the lyrics were, and I'm not sure he even really knew the song. It was a little strange because our partners were there, my fiance and his girlfriend, and he invited me up. Sometimes he makes little comments while he's talking to my other coworkers and adds me in there. Example, while talking to someone else; "Well, you know, it's hard to help with a face as good looking as mine, right (insert my name)?" I just roll my eyes and say something like "pssh, yea, okay". We have different interests, different hobbies and different view points on things. If it were to ever come down to having a relationship with him, I know it wouldn't work. I can make 10 lists on why I should stop thinking about him, how we're not compatible, how bad of an idea it would even be. Not to mention the fact that I do love my fiance and our relationship. I can have amazing sex with my fiance at night, feel like i'm so in love, and then go to work in the morning and with one smile from my manager it's all I can think about. I think about him at night before bed, in the morning when I wake up, in the shower, walking home, on my days off. It's a good thing he doesn't have social media, because i'd probably be on it constantly. TLDR:: I guess the issue is that my relationship with my fiance isn't as exciting as I wish it could be. I've tried to introduce new ways to have sex, more date nights, more flirting, but we always fall back into the same monotony. I want to spice things up more, but don't know how to keep them that way. I used to tell myself that a crush was a good thing (something exciting in a pretty boring life, makes work more tolerable) but that was when it was a month or two old, now that we're on 2 1/2 years I just feel guilty for feeling this way. We have another work get together coming up and i'm more excited about that then my wedding....help!

You should go away on a holiday weekend with your fiance to help each other and find those special moments again that made you fall in love with each other in the first place, throw everything else away, all worries and all other distractions and just focus on each other. Make new plans and get new dreams. But in any case, dont let this crush grow, your commitment to your fiance is much more important than this fleeting thought. Christ bless!