It sure can be hard to grasp, because it's a metaphysical concept. Hopefully you can relate to the concept of narrative, frame is not unlike that. You want to remain in control of the frame of your interaction with women, just like you see people trying to control the narrative of the news. Frame is the same but you just have to control the narrative for one or very few people, not a huge mass.
If you lose frame as we say, it means you're not controlling it and she can control the narrative of your relationship as she pleases. In addition to her disrespecting a man who can't take control, when a woman takes control with a lack of respect for you, she will turn on you.
You can also think of frame like laying down the rules of the game, having her playing the game you have laid out. If she controls the frame, the rules of the game and you don't like the game she's making you play then you'll have a bad time. Giving away your frame is a risk where the odds are stacked against you, most times she'll grow resentful and abuse the power given to her. You must control the frame or fall victim to everyone else's decisions, this is what it is to have a spine.
Saying "masculine frame" is kinda redundant, men are naturally more inclined to control the frame, to influence the direction things are going. Women are naturally inclined to follow and seek a good leader, if you can't control the frame, then you can't lead and thus she will disqualify you. If you can control the frame, if you can lead, the next thing she will check is whether you are a good or bad leader. You can't just force your frame upon someone and expect "having frame" to be the solution to all problems, it must also be something she will want to follow. Even the most alpha of alphas can fail if they abuse their power.
Hopefully I have provided enough context to build your understanding of frame. Due to the nature of it I can't really avoid explaining it metaphorically.
Edit: Grammatical corrections, had a few beers.