first: Marriage with her father? that's pretty nice Oo second: provider in what? third: one sentence do not communicate with another. Think again!

"Mother wanted to be a good provider, a role she has been shouldering since her marriage to Father." Yes, it is correct. Here's why: Mother/Father - these are the names given by the writer (I assume the writer is their child) as he/she addresses the parents, and not common nouns. "...a good provider" is all you need. It's what Mother does. (...a good worker, a good talker, a good runner...) "A role she has been shouldering..." good, this is a relative clause as it tells me more about Mother being a good provider. It all fits. I think DenSam's comments are very, very misleading.