The former Spice Girls singer and her film producer spouse Stephen Belafonte often row over one another's annoying habits, with Mel particularly despising her partner's "unhygienic" bathroom ritual.
Stephen admitted: "I'm always p***ing on the toilet seat.
Mel added: "That is so annoying. Do you understand that it's rude and unhygienic? Whenever I go to the toilet in the middle of the night, I sit in your pee."
Although Mel hates Stephen peeing on the toilet seat, her husband is refusing to curb his bad habit until his wife addresses her own dirty habits.
Stephen told more magazine: "I'm going to keep doing it until she starts putting the lid back on the toothpaste. Her hair gets in it. Do you know how nasty it is to find a really long hair in my teeth when I'm brushing?"
Despite their bickering, Mel and Stephen - who have been married for three years and raise the singer's daughters Phoenix, 11, and Angel, three, and his child Giselle, seven, together - believe they will never get divorced as they have regular relationship counselling.
Mel said: "The good thing about relationship counselling is that problems get squashed before they get too big. We get touch ups on the way, so we'll never get to the point where we're like, 'Oh my god, we're getting divorced.' "
Stephen added: "That is true, we'll never get divorced."
Mel then joked: "I think we'll just kill each other instead."
