This, exactly. Neelix was a pretty unmoored character in a show where each character’s development relied heavily upon interplay on a counterpart. Neelix only had Kes to rely on, but Kes was the Doctor’s counterpart. Mostly, which left Neelix not much to play on, but the jealousy for the first part of the series. It resulted just as you described, poorly.

Once Seven was introduced, and a bunch of other characters could connect to her, and then Neelix could connect to both Naomi and to Seven, everything really fell into place for both Neelix, and for a bunch of other characters. 

Kes was a real drag on the show for so very many reasons. I was so glad when they got rid of her character.