I'm also a "honeymooner," though I call it "Weight loss Attention Deficit Disorder."
I've learned to use this tendency to my advantage - or at least minimize the damage of this tendency, by keeping my weight loss plan flexible and interesting.
In essence, when I start to get bored, I add some new element to my weight loss plan, or even revamp my plan altogether.
To some degree I've done this all of my life, except I would always give myself a "vacation period" between plans. And I'd gain weight during that vacation period, so I wasn't just always starting a new diet plan, I was "starting over" because of that "vacation" period.
So now I just don't give myself vacations between plans. When I get tired of one plan, I'll tweak it, or even revamp it entirely.
For consistency, any way of eating that I want to try, I convert into an 1800 calorie exchange plan.
During the 105 lb weight loss, I have changed or tweaked my eating and exercise plan dozens of times. I've taken my inspiration for food choices from a dozen plans or more - Atkins, South Beach, Neanderthin, Primal Blueprint, Volumetrics, The Zone, The Duke Diet, old Weight Watcher's plans...
I also give myself incentives for meeting weight loss goals (I don't do time-based goals though because I always find those unbearably frustrating, especially if I don't lose quite what I'd planned for. If I miss my weight loss deadline by just a few days or pounds, I see the huge failure not the partial success).
Right now, for every five pouns I lose, I add a bead or charm for a "weight loss" bracelet (a cheapy version of the Pandora jewelry, I get the beads at Michael's or JoAnn Fabric).
I've also considered copying a trick I saw someone talk about here. Using two glass bowls or jars filled with small pretty stones. Each stone represents one pound and one jar contains the stones representing pounds that I've lost, and the other jar containing stones representing pounds left to lose. When you lose a pound you move a stone from the "to lose" jar and move it to the "have lost" jar. If you gain a pound, you do the reverse.
I find it very helpful to make weight loss "tangible" and interesting. Joining TOPS (take off pounds sensibly) has been very helpful as well, not only for the support, but also for seeing that almost everyone else who's trying to lose weight is having mostly the same struggles. If I gain or don't lose one week or several, I'm not "doomed to fail." Some of the most successful people I've seen at my meetings have had ups and downs and slow and not-so-slow patches. The 1 lb every week losses are mostly myth. Most folks see a lot more ups and downs as they get to goal. Seeing this (not just knowing about it) really helps me stay focused...
... but when I get bored (and I always do) I think up some way to make it interesting.