This is a third year when I'm rereading this book, and I'm much more critical of it this time. I generally agree with the three-level concept: dependent, equal, and intimate communion. However, the author's description of the latter is too abstract. In short, he means it as: love from your heart, give your love, and don't expect anything back.
I would suggest The Mastery of Love book instead now. It explains love much better.
The Intimate Communion book describes the theoretical setup but does not address the practicality of being feminine in the modern world and how to switch back from masculine, while I feel it's a must to get ahead in the world. In the book’s defence, it was more realistic when the book was written.
Changing that external force will help women to operate closer to their base feminine. Unfortunately, it's not clear how. The world prioritises masculine energy, and it's impossible to sustain a relationship with one income provider.
Another point which is not addressed in both books: giving love sounds good in theory until you realise that your partner starts using you and your love. Eventually, you’ll be pushed back to a defensive 50/50 relationship (level 2). You do need guardrails on level 3 to make sure the relationship is healthy, sustainable, and love is mutual.
How Will You Measure Your Life? book mentions the relationship paradox that people usually don't prioritise relationships and under-invest in them until there are visible issues. However, it's already too late at that point, and you'll have to deal with the damage.