My wife does not have an income in US and she is no longer a resident and lives abroad in her home country. She is not willing to file her taxes in US or file jointly. (For her own unsubstantiated reasons) .As a result I file my taxes with the status "married filing separately". Is there an exemption that I can file single or file jointly and not have her sign since she has no income in US anyway or a law that will force her to file the taxes or allow me to file "single"?

You can only file as Married Filing Separately.