Moof, I know how you feel. I bought the wrong sized suit for many years. You sound about my size, except I have another 10 lbs on you.
You have to not only get the XL, but also the one listed as "Tall".
They have XL short, XL medium, XL Tall, and XL Xtall. etc. Medium is for about 5'8" to 5'10", Tall is for us 6 footers.