A British citizen who has never exercised treaty rights in another EEA member-state cannot sponsor their family member under the EEA Regulations/EU law. They can only do so under the much tougher UK Immigration Rules.
In order to be able to sponsor spouses and family members under EU law, an EEA citizen must
- exercise treaty rights (i.e. work, seek work study or be self-sufficient with private health insurance)
- in an EEA member-state of which they are not a citizen
- while family life is being created or strengthened.
As a Romanian citizen, your wife cannot be sponsored under the UK Immigration Rules either.
Therefore she needs to meet the requirements for PR (exercise treaty rights (i.e. work, seek work study or be self-sufficient with private health insurance) for five continuous years) in her own stead.
I am not a lawyer or immigration advisor. My statements/comments do not constitute legal advice. E&OE. Please do not PM me for advice.