You're not "weak in that area", as if it is something you should be able to do (i.e. sleep in the same bed and resist all temptation), you are normal. Which is why setting boundaires (not sleeping in same bed) is important.
No one can tell me that any Christian who is stupid enough to sleep in the same bed as their bf or gf (unless in extenuating circumstances, eg no other possibilitiy of accomodation) , is serious about taking God's commands about fornication and marriage seriously.