Well, this turned into quite a messy thing from a simple question.
If you're currently finalizing a divorce, you cannot get legally married in Canada (or elsewhere) as a path to an expedited spousal application. If the divorce is taking a while to finalize, your other option is a common-law relationship - live together for at least 12 months prior to applying.
But to answer a question you asked earlier - if you're currently still married, you cannot get married to the new girlfriend and apply for spousal sponsorship until the divorce is finalized.