Yourself
The most crucial aspect of this approach to intimacy is the willingness to learn, study and evaluate your own behaviour. It is your behaviour that establishes or indeed creates the possibility for your own experience of intimacy.
When in any degree of crisis, most of us, (one might even say "it's natural") will immediately look to one of the conditions surrounding us - perhaps the weather, another person or an event we happen to be in or bad luck.
When the situation involves our partner and we approach our partner from this initial experience of being on the receiving end of some hurt or injury, a victim, we run a high risk of saying something that carries with it an attack of some sort. The attack might be in the words: "Why are you so unreliable?" or in the body language. A simple "You're late" accompanied by lowered eyebrows and a fixed glance.
The agreement you are making with yourself is to always call yourself into reflecting on your "preparedness" for intimacy. Have you slipped into an attack or defensive posture. To whatever degree you have become defensive or attacking, you will not be able to invite your partner into intimacy or respond to your partner's invitation.
You prepare yourself for intimacy by acknowledging that you are the source of your feelings at the time, be they anger, frustration, sadness, annoyance - whatever. Once you make this self declaration, you are ready to listen to your partner or express yourself to your partner, free of attack statements.