These lines are from Act I, Scene 7, in which Lady Macbeth accuses her husband of being cowardly--"so green and pale"--in his wavering about his purpose to murder Duncan. These words of Lady Macbeth follow her radical soliloquy in which she has called upon the spirits to unsex her and make "think" her blood. Clearly, there is a connection between masculinity and violence.
And, so, it is Lady Macbeth who is more masculine than her husband at this point. For, Macbeth's actions do not seem to be in line with his desires as hers are. This is why she asks her husband if he is afraid to act upon his desires by carrying out his plan to murder Duncan so that he can become king. In the cited lines, she asks her husband if he is afraid to be the same man in reality as he wishes to be in his "vaulting ambition," and she tells him that she will measure his love by his future actions, as well, further threatening Macbeth's masculinity.
Evidently, Macbeth resents her emasculating words because he tells her to be quiet and replies,
I dare do all that may become a man;
Who dares do more is none. (1.7.51-52)