Whenever mainstream publications report about a breakup of a celebrity couple (as People.com has in the case of Heath Ledger and Michelle Williams), it’s always because of work pressures and being apart shooting different films, blah, blah.
But in the real world people break up for one of three reasons — infidelity, money problems, or one of the partners having a drug/alcohol problem that isn’t being remedied. Money isn’t an issue with these two and I’ve never heard of booze or snorting being an issue with either (especially with a young daughter to look after) so…anyway, whatever. (An occasional, very obscure fourth reason for breakups — one of the partners realizes he/she will be happier with a lover of the same sex — isn’t an issue here either.)