I've always thought the answer was yes, but apparently, I recently heard a different opinion related to whether or not the marriage that the Kohen got into was a legitimate marriage.
Can someone elaborate on this?
A Cohen may divorce his wife.
The Mishna and Halacha mention special rules for the divorce procedures of a Cohen, so it follows that may do so:
For example, in the laws of how to write the names of the husband in a Get (a divorce document) in Shulchan Aruch, Even HaEzer 129:19 - סימן קכט - דיני שם - it says:
לֹא נָהֲגוּ לִכְתֹּב בַּגֵּט לֹא כֹּהֵן וְלֹא לֵוִי וְלֹא שׁוּם כִּנּוּי, אֶלָּא: פְּלוֹנִי בֶּן פְּלוֹנִי ...
The custom is to not write "Cohen" or "Levi" nor any other accolade in the divorce document. Rather one write Ploni son of Ploni...
The main divorce restriction a Cohen has, is that he may not marry a divorcee, including his own ex-wife.