It's more of a co-dependence. When it comes to military we have fallen behind significantly, but the EU member states also doesn't want to spend a trillion euros a year on it.
It may seem one sided, but the EU has a lot more to gain if there was a hard split between them and the US. It will be significantly more painful for the EU, for a long time, but ultimately it would be the undoing of the US as hegemon. Unfortunately Russia would take advantage and begin an invasion into the EU, so an EU/US split is unfavourable.
Ultimately it is the security of NATO that the EU really needs the US for. And that is what it pays for in the dependency it has on the US.