First, I would recommend that you find a way to spend 15 hours a week together, doing things just for the two of you. In other words, rekindle your feelings, like when you were dating. I have a list of ideas I give out; maybe you can apply some of them.
Also, I recommend finding ways for the two of you to exercise together. It's fun, it's good for you, and it will help her lose the weight; once she does, she'll feel better about thinking of you in a romantic way (trust me). We just got my husband a puppy, and he's exercised more in the last month than in the last 10 years.
Ideas:
Read a book together
Take turns picking out a movie to watch
Bring out the board games, at least once a week
Start a solitaire club with some neighbors or friends, play solitaire against each other one night a week or month
Start gardening together
Grow herbs/vegetables/fruits
Take walks
Start a sport together; take classes at a community college, such as racquetball or volleyball
Get bikes and start riding bikes together
Sign up for an MS 150 and train for the bike ride all year
Plan some day trips, start taking one every month
Try out one new restaurant every week, take turns choosing and surprising the other with it
Go to bookstore and get a book like “52 great invitations to sex” in which you both have 26 invitations for a special evening to invite the other one, and you set it up, give the other the invitation (included in book) and then put on the evening
Join an online gaming community together (but don’t get addicted!)
Buy a Wii or Guitar Hero and play together
Give each other foot rubs
Take massage class together and practice giving each other massages
Go back to school together
Get a pet, take it to obedience school and learn to train it (if applicable)
Join a neighborhood dinner club or other club
Volunteer together
Join a church or get more involved in your church
Take a cooking class together and take turns cooking for each other
Go to HGTV.com and pick out a project to do for your house together
Take free classes at Home Depot on how to fix something at your house
Start a business together
Organize a block party
Organize a family reunion
Start working with a financial planner or learn about stocks together
Take dancing lessons together; if you like it, start entering in competitions
Go online for your city and look up 'activities' and 'family' and maybe even 'free' if your city is big enough; subscribe to those websites and go there every month to look for upcoming activities you can all do together; you can find plays, music events, art things, sports things, picnics, etc.