Weight loss partner

Hello, I am looking for some motivation and looking to lose before Christmas. Then planning drop a lot before June as I want to prepare for an obstacle race. My weight goes up and down all the time because I lose interest. Gained back all the weight I lost and now I need to be more serious about it. Looking for someone I can keep motivated and they can motivate me. What does help is challenging each other. I'm in if interested. Thanks.