I want to know if Iam entitled to half of my husbands house. He was left It by his mother who died after he left me. He said as she died after he left me I'm not entitled to any of it. Is this correct?

In short, no, but it really depends on what your status was at that time.
You might be able to fight for a share, but that would take a good and expensive lawyer..

Left you, without filing for divorce? What state?