They begin to feel a touch of sadness, though not necessarily because of you.
Perhaps a glass of wine or brandy is involved, or maybe a disagreement with a new 'friend' stirs up a hint of melancholy or nostalgia. This sparks a desire to check up on you, leading to them sending a message. We term this "a ping". They "ping" you to gauge your availability, wondering about your whereabouts and well-being. They reach out via text or a call to ensure you're still around. Just for assurance. On receiving confirmation of your presence and readiness to accept them, any feelings of nostalgia or reminiscent thoughts are quickly dismissed.
Whether or not to respond to pings is beyond the scope of this article. All I will advise is to carefully consider your response if they've committed serious transgressions - such as infidelity. But then, pursuing relationship recovery in itself is a contentious activity. Typically, with clients, we advise against responding to initial pings from an ex. At this stage, the no contact strategy begins to unfold its full potential. The balance of power starts to shift in your favor.
However, if you were to signal your ongoing availability and persistent thoughts of them, they would feel comforted knowing they can continue exploring new opportunities without the fear of losing you as an option. Should their current ventures prove unsuccessful, they can always return to you, who would presumably welcome them back after their explorations.
It's crucial to understand that if your ex doesn't "ping" you, it doesn't signify the ineffectiveness of the no contact rule. Some individuals might be more headstrong and resist the inclination to check up on you. The strategy of maintaining silence can still be effective in such instances. So, if your ex remains quiet - remain steadfast.