divorce the right tothe kids??????????

[not so happy in love :(]

in islam when a couple get divorcde and their are kids invovled after the age of nine or seven(different scholars different opinions)
the father has the right to have them im not talking about the countries laws just an islamic lawthis is what i have been told
ok isnt it a bit eerrm dunno uumm of a biased view then the woman has a less of a chance to get out of the marriage if she knows that there is no way that she can islamically get the kids
obviously there is something that i cannot see as islam is not at fault but me so i would like to understand
hope my q makes sense
so basically its ok for the guy to remarry and someone lookj after his kids but the woman cant remarry not much of a bargain is it? or am i missing somehting