No. A separation agreement regulates only the period between separation and the divorce becoming final. It is neither subject to formal requirements nor mandatory. If you and your partner agree on separation arrangements, the agreement needs no special court approval — unlike divorce arrangements.
Even if a court determines separation arrangements, they do not automatically apply as divorce arrangements. Legally, separation remains part of marriage. The marital duty of support therefore still applies during separation; it no longer applies after divorce.
Conclusion: Even if you have a separation agreement, the consequences of divorce are determined anew.