If I understand well what you want, the resume or resume* options to enumerate or itemize environments, defined in the enumitem package let you interrupt temporarily such an environment to insert some text. Usage:
\begin{enumerate}[options…]
……
\end{enumerate}
Some text…
\begin{enumerate}[resume]
……
\end{enumerate}
The resume* option uses the options of the previous list. You may change the restarting index with [resume, start=n].
The package also defines a notion of series of lists. See the details in § 3.4 & 3.5 of the documentation.