Luffy would have to say, he had a pretty cool girlfriend. I mean, when he first met you- you had a higher bounty than him! That was so cool! So, he just knew he had to have you on his crew. Though, he didn't expect you to willingly start dating him as well just a few months after joining. You were still relatively new, but he wasn't complaining.

So when Usopp started to make fun of him for being 'less' cool than you are, and having a lower bounty than you. Everybody was a little surprised when Luffy didn't say anything about it, just nodded. And that's rare, Luffy is never quiet.

"Yeah, my girlfriend's pretty cool." Luffy smiled, "but she's not as cool as me!" Luffy declared, while looking over to you.