I Yell At the Television Like Its a Real Person

Ok, anyone here watch Outlander?

A couple friends are really in to it and I'm considering giving it a chance. But isn't the lead woman married? Or is she married and cheating with the other guy? Or is it the same guy in two different time lines?

Umm not a fan of infidelity fiction so don't want to get half way through a season and hit that iceberg.