Complex sentence: After this marriage a peace was made between the Triumvirs (second triumvirate) and Sextus with the Pact of Misenum in 39 BC. After the war was renewed in 36 BC, Scribonius felt the cause was lost and abandoned Sextus.
Split into simpler sentences: After this marriage a peace was made between the Triumvirs and Sextus in 39 BC (Peace of Misenum). In 36 BC after the war was renewed, Scribonius felt the cause was lost and abandoned Sextus.