Loosing weight

So I recently got back in the pool after 1040 weeks of rest(20 years). When I swam in college I was a middle distance swimmer and like a lot of mid/distance guys worrying about my weight was never an issue. At 6'5" i weighed a whoping 139 freshman year and 160 senior year. 12 months into my hieatus I weighed in at 215lb where I have been +/- 10lbs ever since. When I got back in to the pool 9 weeks ago I weighed 223lbs. I have never considered myself vein however the tire around my waist partially covered by my board shorts was a little embarrassing. After some gentle coaxing by my coach I bought a jammer and started a diet. I believe his words were something like, "we have one rule and that's guys have to wear drag suits or jammers, but in your case he would wave the rule until I shed 30lbs". That's how I remember it anyhow! I set a goal of 190lbs which equates to a BMI of 18.5 and ~11% body fat. I looked around for something that would enable me to manage what I ate and how much I ate and was recommended MyFitnessPal. I have used the app religiously and have so far lost 27lbs and hope to hit my target before Christmas. Now that I am nearing my target I am worried about moving from weight loss to weight maintenance. Does anyone have any suggestions on transitioning from Weight loss to weight management and how to stay motivated. I plan on being competitive again with my swimming but want to keep the weight off but not drop to an unhealthy weight. Any help is appreciated.