We do a lot of complaining about the way women’s roles in action movies are typically that of the romantic interest. And hell, it’s justified. There are far too many films where the lady, however interesting she is, is nothing less than window dressing or the arm candy.
However, on the other side of this coin, it’s important to remember that having a romantic interest does not inherently lessen the worth of a female character. It’s only when her role boils down to ‘my only motivation is my love for my amazing prince charming dudebro’ that it becomes a problem.
Consider The Avengers. Does it matter if Clint Barton and Natasha Romanoff have a thing? I’m not necessarily arguing that they do, but if they did, would it make Nat any less kickass? No. In this case, the Black Widow is a well-rounded, complex character with various motivations, and romantic feelings are just one part of those motivations.
On the other hand, let’s look at Sherlock. Irene Adler is also an arguably badass lady. But over the course of her part in “A Scandal in Belgravia”, all of her actions are motivated by her romantic attachment to Sherlock, and it makes her character unpleasantly two-dimensional.
The problem with boiling women down to just their romantic motivations is that it essentially removes their agency, and forces us to define their characters in relation to their romantic partner. But at the same time it’s important to remember that the basic fact of having a male romantic partner does not immediately make a lady less kickass.