"Gratitude. The feeling that has consumed me all season and especially now at the end of this journey. Thank you Hannah for the opportunity to pursue your heart. You will always have a little bit of mine after the time we were able to spend together," Peter wrote.
"Thank you to my brothers from the house. I know we all learned a lot about ourselves during this experience and I'm so happy I was able to make these memories with you guys. Thank you to @bacheloretteabc for giving this hopeless romantic a once in a lifetime experience I will never forget."
Along with his post, Peter shared a photo of Hannah and himself cracking up during a live segment of the finale when they were being interviewed by Chris Harrison in which Hannah revealed they actually had sex in the Fantasy Suite -- a windmill in Greece -- four times instead of just twice, as she had previously disclosed.
Peter also posted a cast photo in addition to a video he had filmed of himself before filming of The Bachelorette's fifteenth season commenced. (He gushed about how excited he was to meet the Bachelorette and give the process his all).
"Thank you to my amazing family for always having my back, I think everyone understands where my emotions come from now. Thank you to my friends for giving me more windmill jokes than I know what to do with," Peter continued in his Instagram post.
"And thank you Bachelor Nation. I have felt your love and support since night one and I couldn't be more thankful. Everyone on this planet deserves that 'indescribable, words won't do it justice, make your heart skip a beat' type of love. Never stop until you find it."
Hannah said letting Peter go not only broke his heart but her own because she had truly been falling for the pilot from California.
"I woke up that morning honestly and had to follow my heart. It was really hard for me too," Hannah explained of why she broke up with Peter during a live segment of the two-night finale's first broadcast.
"I think maybe I wish I had known a little bit sooner about how you felt and you would've told me, because I was scared... I think I felt like you were scared to love me -- if I can think of anything [that wasn't perfect] -- and that you were apprehensive about sharing your feelings."
When Peter was ousted in Greece, he admitted he "didn't see that coming at all" and was really convinced at the time it would be Hannah and himself engaged at the end.
"I'm not mad at Hannah... [but] it hurts like a b-tch right now," Peter sobbed.
"But I'll never forget this journey -- how beautiful it was in so many ways. I found love with her, and I swear I don't regret anything. I know I have a ton of love to give, and I thought it was Hannah. I truly did."