dailydoubtingbee: I’m going to copy/paste something I wrote to another woman on these boards regarding a similar situation (with some changes to personalize it regarding ambivalence a bit):
I just wanted to chime in to say that this can 100% be normal. God, if I could count how many times I’ve felt ambivalent towards my s/o, I’d probably still be counting. 
I hate this mentality that people have to be over the moon and pooping rainbows when they get engaged and I HATE the phrase, “doubt means don’t.” No, it doesn’t. Various studies have shown that the honeymoon phase (the butterflies, excitement, etc) can end anywhere from 6months to 2yrs into a relationship (obviously there are exceptions). I have terrible anxiety (and depression) that has manifested itself in my relationship (due to both of my parents getting divorced when I was so young, a bounty of crappy relationships, and a chemical imbalance in my lovely lovely anxiety-riddled brain). It latched onto my relationship six months into us dating. I had doubts. “Have I fallen out of love with him?” “Maybe I love him, but I’m not IN love with him.” I went through periods where there was NO attraction or feelings of love for him at all. I would get SO afraid that I would cheat one day. Sometimes, I had to FORCE myself to stay. And, you know what? ALSO NORMAL. Relationships ebb and flow. I have been with my now fiancé for over 2.5 years. Six months in, the ambivalence started for me (which is, not so coincidentally, when I was like, “Holy crap, I could marry this guy!”). I was devastated because I was sure that meant that I didn’t love him “like that” anymore. It turns out, I had to change how I looked at love and I had to get in tune with myself and learn about myself and my expectations of what love is.
Love is not a feeling. I repeat: Love. Is. Not. A. Feeling! Love is a choice through and through. I don’t believe in soulmates. Is there someone out there who is better for me? Maybe. Is there someone out there that is better for my fiancé? Probably. Could I/he be just as happy or happier with someone else? Yes. There are billions upon billions of people in this world. To assume that you are meant for ONE person is, in my mind, a bit farfetched. To me, what makes my relationship with my fiancé that much sweeter is that I choose HIM every single day even though I know he or I could be just as content with someone else. That makes love so much more wonderful; knowing that it is not a feeling but a choice. He CHOOSES to love me even when he can’t stand me. Sometimes, I want someone else. Sometimes he does. We’re human. We get annoyed with each other. But, we choose one another every day and we’ve made a commitment to always choose one another, even when we don’t like each other at all. I still, due to my anxiety, have moments of, “What if I’m making the wrong decision?” “What if I’m just comfortable?” I’ve learned how to silence those voices. They play a lot, but this my demon and we all have our demons.
Transitions are scary. People react to them differently. Not every person is stoked and over the moon about getting married. A lot of people experience exactly what you’re experiencing. I did/am/will be until I’m six feet under. What I’ve learned is that’s who I am and I will always go through periods where I’m uncertain and scared and confused, because it’s how I’m wired. When I think about our wedding, I become scared sh*tless (excited, but holy crap scared). It’s a massive commitment and the idea of being with one person for the rest of my life scares me to bits. Men are allowed to feel this way. The media celebrates it: the groom with the cold feet and the “only one lady bit forever” freakout. A LOT can arise when you’re about to get married. Some women throw themselves into wedding planning and never really connect with their feelings. Some women are filled with butterflies and stay that way until the day they die. We’re all so different and that’s okay. One of the most monumental things of this growing process over the years for me is that I learned that it’s okay to not feel okay. It doesn’t mean that your relationship is crappy. In my opinion, the fact that I was able to work through my confusion and the fact that I was able to choose love and to choose my s/o despite it all, sets me up to be in that percentage of marriages that do last. You’re not running from your feelings. You’re not hiding behind butterflies or centerpieces. You’re facing them head on. This is good!
TLDR: Yes, it’s normal to marry someone you’re not 100% passionate about because passion fades. Then, passion reignites. And then, passion fades again. Feelings, in themselves, are ephemeral. They are fleeting. This is why it’s important to choose love, not to wait for yourself to feel it. I’ve found when I choose love and I perform loving actions towards the man I’m with (even if I’m feeling ‘meh’), those butterflies reappear from time to time. Then, they flutter away again. It’s incredible how much more I appreciate them now that they don’t come up much as opposed to when I had them all of the time at the beginning of our relationship. If you’re in the mood for some more reading, I highly recommend, “Getting the Love You Want” by Harville Hendrix. Chin up! You’ve got this!