The couple are said to be back together following a rumoured split last month, which was blamed on the pressures of Williams recording his new LP.
Field has apparently now told friends she has stopped drinking alcohol in preparation for starting a family.
A source said: "Robbie and Ayda are really back on track now and one of the things that helped them bond was playing with Jonathan Wilkes's son.
"It’s no secret that Jon helped get the pair back together, and he's been spending a lot of time with them at Robbie's Hollywood home.
"But the balm that really soothed tensions was Mickey, Jon's son and Rob's godchild. Spending time with him made Rob realise what he really wants."