What exactly was Travis and Elisabeth shimer's relationship before they split? were they married? Why did they split/divorce?

From what I read on the daniel larson wiki, it apears that Daniel's mom Elisabeth met his dad Travis in 1995 while enrolled in Antelope Valley community college, as Elisabeth was enrolled there from 1995 to 2004. Daniel was born in 1998.

Since Elisabeth's legal name was still Shimer and not Larson like his dad Travis, were Daniel's mom and dad ever legally married or officially a couple? Cause I am confused on how or why Daniel's legal name is Larson but not Shimer like his mom.

Why exactly did Travis and Elisabeth split? The wiki was vague with no details