Well there are several ways to say this differently. But it can depend on the context, viz. what exactly is "it"? I am sure there are other expressions, but here are 3:
For example, if "it" is the necessity to change the faulty gear box in your car (which will be expensive) - you might say: "There's no alternative."
If you have made a firm commitment to someone, e.g. promised to marrry someone, or promised to lend someone some money, but you are having second thoughts, you could say: "There's no getting out of it."
If you have made a very bad mistake that you cant rectify, e.g. you have done something illegal and consequently you will always have a police record, which will affect your job prospects, you might say: "I'll just have to live with it".