From the UK Daily Mail:

It's a bit of a cliche that women settle down for love, and men for regular sex.

But scientists are claiming it's true. A study shows that women agree to cohabit because they view it as a stepping stone to marriage.

Yet men move in hoping for more sex and to 'test drive' the relationship to see if it is worth sticking around.

The findings are likely to raise doubts about whether cohabitation carries the same degree of commitment from both partners as marriage.