What she lacks in age, she makes up for in madness

I heard a song at work today and I love it, but I cannot find it for the life of me. I only remember one line, and typically with a light search, thats enough! Not this time. 

It’s a band, not just an artist.  Their frontman is male, baritone voice. Definitely rock. I have only heard that song of their so I could not tell you what subgenera they were.

The line is

‘I will be in love with you, until the end of time”

But the way he sang it was more like

 ’I /will /be /in love /with you,/ until/ the end /of time/eeeeeeeeeeeeeeeee/”