How can I save my relationship?

Maybe you should look at this long term, what do you want in 5 years... do you want to be with her, in her family, can you see a life together? Or do you just think it's not worth the trouble? It sounds to me like her family were the ones convincing her to be with the other guy, and under persuasion of people that are close to her like that, the fact that she came back to you a second time may really mean that she's prepared to be yours, i mean... Why would she give up her ex to be with you just to go back to him? But of course i can only comment from what you've written, but relationships are built on trust, as cheesy as that sounds, so either decide that she is yours and yours alone, or decide that it is not worth it, whining and being immature really won't help anyone. Best of luck, i really feel for you.