In the last few years I've lost more than 40lbs and increased my strength tremendously. Health was the reason to keep me going through with it. Looks can only motivate you so far. Listening to your explanations leads me to believe that you need a sustainable long term solution that has flexibility. I'll give you my fitness and diet recommendations below:
Fitness:
Variety! Boredom will kill you otherwise. You live on the second floor. One day can be stair day. Climb up and down them for 15 minutes before you shower for the evening. If it becomes easy, get small weights or spend a little more time. Swimming is great. Pick a day or two as swim days and go early in the morning. Early risers will probably be older or professionals. You will be less conscious around them than the young and out hunting crowd that comes later. Plus the kids aren't there. Walking. Pick a day to walk some trails or such. Yoga and similar programs. Take a class one day a week. The stretches will help the other exercise be more effective and they will improve your aches and improve concentration. Bikes. Take a class or ride one once a week. I hate sitting on a bike. A day a week will do you good but not bore you back to your TV and Doritos. Buy a fitness ball and a book on ball exercises. This is one of the best bang for buck workout tools I know. Buy a book because videos are usually 15 minutes of generic stuff. Pick a day for a ball workout of 30 minutes (you can do in front of the TV). On days you don't have time to swimming, biking etc, work in the ball or stairs. There is a full week without being repetitive, overwhelming or expensive.
Diet:
As much as we don't like to hear it, diet is at the center. What I did was create my own "cheaters" diet. I put everything that I know is worst for me (high sugar things) into a cheat category. I can eat a cheat anytime I want to, I just can't have another for a week after that. That makes me wait for the things I love best so not to waste my cheat on garbage. They also taste better due to the anticipation. I still let myself eat fries and other fast paced garbage but I made a goal to eat more healthy meals than I was before. Start with 4 or 5 good meals (veggies, baked, etc) a week as a goal. It's not such a drag when you know you can have fried chicken tomorrow. If you completely deny yourself the things you love, your diets tend not to last. The biggest benefit to me for the diet side was still the health aspects. I feel better and I know I'm healthier.
I hope that helps. Notice - no gyms. I love them now but they are NOT required to become fit.