<human>: Can you succinctly summarize the text in 1-3 sentences?

My [27F] fiance Jacob [30M] is a sweet, caring, wonderful man, we've been together for 5 years. I can imagine spending the rest of my life with him, I'm very happy with him and feel lucky to be marrying him. However, I see these posts on reddit about men/women saying how they still want to jump their husband or wife after years of marriage and how enjoyable the sex is, and I don't know if I have that. 

We enjoy each other's company very much. We still have date night, we make an effort to do activities together and keep the romance alive. We have intimacy and comfort, but I feel like I just don't have those lustful feelings anymore and the sex isn't something I look forward to as much, if at all. It's pretty vanilla and although we've talked about it and tried to work on it, I wonder if this is just how all marriages will end up. 

I felt like when I decided I wanted to marry him, sex wasn't as important to me for marriage as the affection, love, support and trust I felt with Jacob. Now I'm not sure if that was the right choice because I started having a crush on my coworker, Cooper [28M] in the past couple of months. 

I know it's irrational and I would never do anything beyond thinking, but I sometimes imagine what it would be like to kiss Cooper and I feel flutters and lust. I make sure to talk about my fiance at work and keep everything very professional, but then I wonder, am I doing the right thing in marrying Jacob? Is this normal for marriage or are we going to end up like /r/deadbedrooms? How do couples keep the lust going?
<bot>: Started having a work crush, feeling lust for crush but not for fiance. Now having a little bit of pre-wedding jitters.