Enrique Iglesias doesn't think ''perfect relationships'' exist.

The 'I'm A Freak' hitmaker has been in a strong relationship with partner Anna Kournikova since 2001 but says there can be ''bad times'' between every couple.

He told the Metro newspaper: ''You go through your good times, you go through your bad times.

''It's a tough thing for me to believe there's such a thing as the perfect relationship. I don't think that exists.''

Meanwhile, the 40-year-old singer couldn't help but gush about Anna recently, admitting she is the ''coolest girl in the world''.

He explained: ''Firstly, she's the coolest girl in the world. And she understands who I am, to the point where she's willing to sacrifice her personal time with me and let me do my music. It's a huge sacrifice and I respect that tremendously.''

And when it comes to the bedroom, Enrique insists sex should be inspirational.

He added: ''Sex has to inspire you. If you don't care about the person you are with or the situation, then the sex is bad ... Well not bad, but, you know ... But also, I honestly believe it's difficult for love to survive without sex.''