Holmes says she is "addicted" to the band. She has eight tattoos of the Irish group and has spent £30,000 traveling around the UK to see them on tour.
Her husband told her "Choose Westlife or me."
The 44-year-old fan opted for the Westlife instead of her man according to reports in the Daily Mirror.
She said "I think he thought I was joking but he soon realised I wasn't. I always get stopped in the street and he couldn't hack the attention I was getting.
"The concerts take up a lot of my time and money. Westlife are a really big part of my life. I'm completely devoted to them and the tattoos are my way of showing my loyalty. I like to think I am their biggest fan.
"It's my only hobby. I don't smoke, I don't drink, so Westlife are my only addiction."
Here's a video of their most popular song: