Surprise

"Well, I'm not sure if I'm getting married because I don't know what your answer is." Blade's anger instantly faded when Ian took the box of the rings out of his pocket and said this which made the latter look dumbfoundedly whispering "Huh?"

Ian chuckled because 'Huh' was not one of the things he expected Blade to say but he took a deep breath and let out " I'm so nervous." He glanced at Eric who has been encouraging him for four days since that was his idea in the first place to bring Ian and Blade together.

He kneeled down on the ground and opened the box to show the beautiful custom rings that he himself designed and said after gathering all the courage that he had left "Will you marry me, Blade?" 

Blade looked around seeing Liam, Eve, Mace and Eric were there as well as Ivan. So this is what they were hiding from him and this explains why they were acting strange.