Everyone has given some great advice. I've maintained weight loss for the past two years for longer lengths of time than I've been in losing mode, so I feel pretty practiced at it. So, my first piece of advice is to go slow. Don't burn yourself out, which it sounds like you may be. Half of this, for me, was changing mindset and habits, which can take a WHILE and come on SLOW. When I was trying to marathon lose, I didn't learn very many good lessons. While I get frustrated with my mental plateaus in weight loss, I realize that each plateau is really just me taking the time to entrench even better habits, because as I get smaller, it gets harder. There is no magic cure that can replace this process.
I second the weight lifting and running. I recommend to everyone that they buy The New Rules of Lifting for Women. I love it, love it, love it. I got off track with it at the beginning of this summer for stupid excuse reasons (lots of summer travelling and whatnot), but if you already have a gym membership, it is an AWESOME book to teach you how to really use all those weights at your disposal. Be wary, however, in that lifting can make you more hungry. I don't count calories and usually just try to read my body and stick to routine, "safe foods." When I started lifting, however, I stopped losing weight. I figured out that I couldn't always trust my hungry feeling when weight lifting, as it was making me consume too many calories. Instead, I had to start eating smarter (more filling protein and whatnot). So, lifting can be a bit of a double-edged sword.
Also, I started running at 230 pounds, but it started on a treadmill. I now run outside, but like GlamourGirl said, it's like starting all over. Good shoes are an absolute MUST, and while everyone's form is a bit individual, reading up on good form is also a must. Some people just hate to run, however, and I often need some other kind of cardio, because I get burnt out. Check out your gym's classes for something fun. I find that when I go to a class every week and people are expecting me there, that one day of structured exercise keeps me structured the rest of the week.
Also, this: "can't say "hey babe let's go out to eat because we're married and i love you! let's have dessert!" Some people would say you have to retrain your brain not to associate celebration with food, and as a whole, you do have to a bit, in that you don't need to be celebrating every small success and bemoaning every disappointment with a pint of ice cream. I am going to tell you, however, that there is nothing wrong with celebrating with dessert. Just PLAN for the dessert. If you know you are going somewhere where you will really, really want that dessert, then lighten up on your food consumption for that day. Give yourself some wiggle room. There's been times where, naturally, after deciding I was just going to do it and have a blowout meal of really good food, the next few days I just didn't want to eat as much food. That was not always habit, however, and it took a while to get here. There's just some things in this life I decided I can't do without, and I was going to work around how to enjoy them. Pizza and a thick slice of rich, homemade keylime pie are two of them.
Also, on the food front, finding healthier versions of some of my guilty pleasure food has been great. You do not have to feel like a rabbit.
I just had lasagna last night with zucchini as the noodles... Still a little too much fat probably, even though I did small portions of low fat cheeses and lean hamburger, but it almost tastes better to me than the real deal, and it's even one of my boyfriend's favorite recipes. Finding awesome, healthy recipes for home has been a big deal for me.