This yeast strain is known to produce a lot of banana ester, as well as bubblegum and pineapple. Next time perhaps you would prefer to try BE-134 or Belle Saison yeast instead of the BE-256.
You also fermented fairly warm at 68 F, which tends to favor the esters. If you try fermenting cool around say 62-64 F, perhaps the banana ester would be more muted or even non-existent. I know when I have used Belgian yeasts that cold, they come out very clean and at times even lager-like in character or lack thereof. So you could always try the same yeast fermented colder and see if that's something you might prefer.
Fortunately, time can also help with this. I find that even in the most banana-flavored beers, this ester tends to fade away completely within about 3-6 months on average. So if it is possible to age your beer for that amount of time, perhaps you will be able to enjoy the beer much more after the aging.
Better luck next time!