You do not have to prove lawful residence in the host member state for the three years. All that needs to be proven is that you and your ex-partner spent a year in the Host Member State (the UK), as married partners.
Your question is regulated by Directive 2004/38, in part under Article 13 paragraph 2 (a).
References under Article 13 paragraph 2 to children or to domestic violence do not appear to be relevant insofar, as the facts you relate in your question are silent with respect to either of these factors (children or the existence of domestic violence).
Under UK law, the short answer to your question is that you will be required to prove that your ex-spouse was exercising a right of residence under the Directive or EU law, at the time when your divorce decree absolute is pronounced.
UK law does not allow you to invoke an independent right of residence independently.
I. EU law, Directive 2004/38 Article 13 paragraph 2:
Article 13 paragraph 2 (a) provides as follows:
2. Without prejudice to the second subparagraph, divorce, annulment of marriage or termination of the registered partnership referred to in point 2(b) of Article 2 shall not entail loss of the right of residence of a Union citizen's family members who are not nationals of a Member State where:
(a) prior to initiation of the divorce or annulment proceedings or termination of the registered partnership referred to in point 2(b) of Article 2, the marriage or registered partnership has lasted at least three years, including one year in the host Member State;
[....]
Before acquiring the right of permanent residence, the right of residence of the persons concerned shall remain subject to the requirement that they are able to show that they are workers or self-employed persons or that they have sufficient resources for themselves and their family members not to become a burden on the social assistance system of the host Member State during their period of residence and have comprehensive sickness insurance cover in the host Member State, or that they are members of the family, already constituted in the host Member State, of a person satisfying these requirements. "Sufficient resources" shall be as defined in Article 8(4). Such family members shall retain their right of residence exclusively on personal basis.
Accordingly, you must prove prior residence for 12 months in the UK as condition for the retention of your right of residence in the UK.
On the basis of the facts elicited in your post, it appears that where you are able to prove your claim, you may be eligible for the retention of the right of residence under Article 13 Directive 2004/38.
II. UK law: Regulation 10 (5) of the EEA 2006 Regulations.
Article 13 paragraph 2 (a) in turn is transposed under UK law in the form of Regulation 10 (5) of the EEA Regulations 2006 (
http://www.legislation.gov.uk/uksi/2006 ... on/10/made).
The 2006 EEA Regulations appear to take a restrictive interpretation of the entitlements enacted under Directive 2004/38, which is inconsistent with the principles of EU law, as reiterated on many occasions by the Court of Justice of the EU (most notably in case Metock case C-127/08 at paragraphs 84 and 93).