Addiction prevention process

You should not punish yourself, forgive yourself. You aren't a bad person for relapsing, it's just part of the journey, it happens to everyone. If you believe you are a bad person, you will do bad things, it's a self fulfilling prophecy.
Also, sit ups are shit, do pull ups and push ups, get some push up bars to get better range of motion and a doorway pull up bar (You don't NEED these, but they make it a lot more convenient to get a good workout in).
You can get stuff like this at any sports store, either used or new. Here are some examples of what to look for.
Push up bars https://www.amazon.com/gp/product/B07Q1W8Q27/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
Pull up bar https://www.amazon.com/Pure-Fitness...up+bar&qid=1566329101&s=sporting-goods&sr=1-6

 

Doing sit-ups is a good way of exercising your body but there are still more way to exercise bro. Take up a sport, go for a walk, hit the gym,... There are so many more to explore, why stick up to just sit-ups ? If you want to get ripped and six abs stuff like that, then I highly suggest you do some abs workout which will be way effective than sit-ups. Even if you are tired of exercising, you can start reading, meditating, meeting up people in order to prevent further relapse. However, keep in mind that relapse is a part of the process , not something you should punish yourself for. Each relapse has its own problem and you need to fix it. That is how you get better in the NoFap journey