Alexander, a childhood friend of Spears, walked down the aisle with the TOXIC singer in an impromptu Las Vegas ceremony in January 2004 - only for the star to file for an annulment just 55 hours later.
But Alexander admits he was particularly hurt when he learned that Spears has walked down the aisle with Federline in September (04), just months after his own brief union with her ended.
He tells IN TOUCH WEEKLY, "People break up and you go on your own way but you don't go, 'I love you, baby, and I can't wait to see you,' and then one day you call and the phone's cut off and then she's dating and married to someone else.
"Why is it so right with him and not me? Everybody thinks it's a joke - it's been hard.
"Her life went back to normal and mine didn't. It got all messed up. I've thought about her. I loved her and from what she told me, I thought she felt the same way. Then all of a sudden, this person just disappears. It's hard when I see her face on TV.
"I'm bitter and I'm mad, but I don't hold it against her. She's Britney."06/05/2005 19:15