Reluctant ally is the right word when Germany relies on Russia quite so much. Whenever a diplomatic issue pops up Merkel has continually been much easier on the Russians then other Western leaders, that extends beyond just economics. Soviets and Americans were allies in WW2. Why has Merkel continued to work well with the Russians despite that Putin has a track record of being very rude? Most world leaders spergout over Trump being a bit rude.I'm thinking ally might not be the right word. Economic partner, definitely. I doubt Western Europe has put the Cold War completely behind them, and I'm certain Putin hasn't - that's probably why he wanted Crimea so much, demographics of the region be damned.
"He's afraid of his own weakness."
The goals of EU and Russia are opposed, but that's my point, Germany's interests at some point have to come before other European states, Russia appeals to the necessity of some of those interests. Their relationship is based on necessity rather than simply economics. Europe struggles to find fossil fuels and Iran being sanctioned empowers the Russians further.