Isn’t this like the last thing Blaine can give to Kurt? He gave him all his first, he gave him so much.
First real kiss, first gay friend, first time, dates, presents, first real dance, support, he gave Kurt all his love, he protected Kurt, he let him go because he knew it was killing Kurt to be stuck, yes he even gave him pain, he promised him to take care of his dad, he gave him so much.
And this, a proposal, the promise to be his forever, so everybody should know it, a real ring, he promise Kurt his whole being. He’ll promise Kurt to be his, only his, to never hurt him again, to love him, support him, more than ever before.
Isn’t this the last thing he can give him? The promise of forever, forever being his and walk with him together through all the new firsts? Finding a job, living together, being parents, being a family?
This will be Blaine saying I’m sorry, but I mean it, I can’t lose you, I love you and I want to be yours, I want to give you everything and hope you can give it to me in return, to forgive me, to love me again, more, stronger, because I mean it, I only want you, forever.