Welcome to healthcare magic.
From your history and description, I would definitely consider scabies
. It is caused by a mite invisible to naked eye. It could take some time before your partner manifests symptoms.
The treatment for this involves a single overnight application of 5% permithrin cream in all the body areas except the face. Both you and your partner need to be treated simultaneously. You can also take an antihistamine like levocetrizine at bedtime for 10 days.
Hope this helps you.