In the end, long-term relationships are going to turn habitual in some form or other. We are creatures of habit....

However, it's important to not let all the habits formed be non-constructive. You say you don't talk and just sit in front of the TV so what about starting a new habit where you guys maybe take a 10-15 minute walk and just talk about whatever's on each others' minds? Go rollerblading or start exercising together. When I started working from home last month my husband and I started the habit of my walking with him to and from the train station where he catches the train to go to school and work in the mornings and evenings. It's about a 10-15 minute walk one way, and it's nice because
a) it's a good way to get some fresh air and relax, and
b) it gives us time to just talk and see how each other is doing.
Regardless, if you guys want this to last you have to find ways to communicate and listen to each other (most important), help each other, and fulfill each others' needs. Make the time together quality rather than just filler.
I agree that you should spice it up a little from time to time. So maybe once a week or a few times a month get out of the house and do something out of the norm. Go camping, get away for a weekend, have a small dinner party or a game night with close friends, go out to eat at a new restaurant, see a play/movie/concert, find a free event and take her to it, start taking a fun class (cooking, art, music or whatever) together. You guys can find something that you both enjoy (rather than the usual TV stuff) and do it.
It doesn't have to be fun and games all the time (perhaps occassionally). Just make sure the time together is well spent.