Admiral Sir Ben Key, 59, is suspected of breaking Navy's strict 'service test' - which effectively prohibits relationships between commanders and their subordinates.
Admiral Samuel Paparo, who heads up the US Indo-Pacific Command, said his forces had noticed a 'quick change' in the manoeuvres of the People's Liberation Army (PLA).
Martyn Rigby, 35, paid over £200 for a 'platinum' Admiral insurance policy to protect when he and his wife of three years Mariana, 36, moved to their home in January.