It really comes down to personal views, and as anything it can be very complicated very fast. That's in my opinion the very reason divorce go through trial, as everyone has a different opinion on what the question is.
For instance if you raised a kid for 15 years, divorce for unrelated reasons (ex: repetitive adultery), but take the opportunity to have paternity checked, are you less of a parent of this kid than his biological father ? I'd suppose there's a variety of answers depending on each one's walk of life.
For instance if you raised a kid for 15 years, divorce for unrelated reasons (ex: repetitive adultery), but take the opportunity to have paternity checked, are you less of a parent of this kid than his biological father ? I'd suppose there's a variety of answers depending on each one's walk of life.