"Thank you for being my first love. Thank you for always encouraging me, thank you for keeping me out of trouble, thank you for the times you took care of me when I was sick and depressed.
"Thank you for loving me," he continued. "If you haven't already I hope you one day find love. If you loved me that much when we were young I can only imagine how strong and powerful your love is now. The way your heart is made it's amazing. I know we were only kids when we dated but you taught me what love is."
He then went on to say he hoped the man lucky enough to end up with Sanchez Aguilar treated her with care.
"I hope he knows who he has in front of him, I hope he shows you love and loyalty every day. You deserve that and more," he added.
"My point in all of this is, you are the reason why I know how to love someone. You taught me love, you taught me how to deal with my anger, how to deal with my depression and how to live life to the fullest and I'm grateful for you. I wish you love and happiness."
The text quickly went viral and has generated nearly 100,000 retweets, more than 411,000 likes and thousands of mixed comments.
One woman said, "This isn't beautiful, but that's me."
Anther explained if she was the new girl she would feel a "little weirded out" her man would want to send a text to his ex and express his feelings.
"I would die if I moulded a man to be the perfect husband for another woman."
Another commented: "So basically thanking you for moulding him to be the perfect husband to someone that's not u? feels unnecessary."
"Looool I'm sorry I'm not built like this but this is sooo unnecessary. he still loves you girl," added another.
However, not all agreed it was strange, with many praising the man for his maturity.
"This has to be the most beautiful thing I've read. Shout out to both of y'all for being such damn good people," one person said.
"Imagine having an ex this mature."
Among the string of reactions, Sanchez Aguilar jumped in to offer clarification.
"We were extremely young. We lost our best friend to suicide which is why we have so much respect towards each other," she said.
The young woman, who said she was speechless by the gesture, posted a screengrab of what she had written back to her ex after receiving his message.
"Dude I'm crying. First of all, congratulations on all your beautiful blessings that are coming your way. Thank u for being there for me when I needed you. Thank u for your kind words. I am so unbelievably proud of you, you did everything you put your mind into & you killed that sh*t," she wrote.
"I'm happy you found the woman you want forever with. I'm happy you're happy. You're an amazing father to your daughter. Your fiance is such a beautiful soul, and you have such a beautiful daughter. Again, congratulations on your marriage. I wish you and your beautiful family nothing but beautiful blessings."
Sanchez Aguilar had some words for those who criticised her ex for reaching out to her to reflect on the love they once shared for each other.
"To the people saying they would cancel the wedding if their ex did what my ex did," she wrote. "In my opinion, I don't see why you should … he never flirted with me, he simply thanked me for helping him be a better version of himself, and he wish(ed) me love and happiness …"
Sanchez Aguilar told BuzzFeed she didn't know what to say at first.
"I started crying when I read the text — it warmed my heart that I helped him be a better version of himself," she told the publication.
"We lost a best friend to suicide, and we helped each other heal. I feel like no matter what happens, he and I will forever have respect towards each other."
The reason Sanchez Aguilar shared the texts on Twitter was to show that just because things don't work out with someone "that doesn't mean you should have hate towards them".
"Regardless of everything, you were meant to be a part of that person's life and them yours," she said.
For those asking why they didn't end up together, Sanchez Aguilar explained: "It's not that he wasn't a great man when we dated because he was/is a great man!
"We just didn't work out and that's fine!!! Relationships don't always end with hating the person. It just simply doesn't work out!"
