Married young and regretful

I'm 21 years old and married to a great guy. We met in high school, but didn't start dating until a few years after. We started dating and had so much fun together. I have been in emotionally/mentally abusive relationships in the past, so it was a relief to be with someone who finally treated me well!
We got engaged after 5 months of dating and got married almost a year later. At this point currently, we have only been together for 2 years, married for 7 months of that. He's a great guy, with a slight drinking problem, but he is good to me. Here's the kicker:
There is a guy that I dated on and off between my not-so-great ex's and my many breakups. We were perfect together, however, I knew it wouldn't work until my head was on straight. I let go of my ex--finally!--, and began a relationship with the great guy who was always there for me (we will call him "K"). The connection that K and I had was like nothing I've ever experienced; we were crazy about each other, had AMAZING chemistry in the bedroom, and I was so incredibly happy with him ... Until he moved back to his home state. While I wanted to go with him, I was in college and I broke things off.
When my husband and I met. I felt anxious at the beginning, knowing I still had things to work on with myself and my feelings for K, but I felt confident that I would get through them and hoped my feelings for K would fade.
Seemed like a great plan! From the start, I would lie awake thinking of K, wonder if I should go through with my marriage, and ask myself if this is what I really want. I was panicking before my wedding about the decision, but my husband reminding me of how much he loves me and how grateful he is to have me. I felt the same, but I've felt deeper love with K than I have with my husband...
I went ahead with my wedding, in fear of hurting my husband and making the wrong decision in the long run (What if K and I didn't work out, and then I've ruined a relationship with a great guy because of over-thinking). I recently reached out to K, wondering if the feeling is mutual, and he acknowledged that the feelings are mutual. He expressed regret for letting me go, even though it was me who made the decision, and let me know that he is going to stop interacting with me so that I can have the time and space to make my own decision.

So here I am, married at 21, and in love with someone else. I realize that this seems a little silly, considering the fact that both guys are great and I still have an issue. I also realize that this forum may not be the place to find an answer, but I thought that talking about it may help! Any advice is appreciated!