I would prefer stories that do not have explicit cheating or mpreg. Smut is fine, though, as is angst with a happy ending.
Many thanks! :)
Edited to add: I've read or at least checked out all of the recs from Kurt/Blaine as Dad and Blaine/Baby Fic. (So if you're also looking for single dad!Kurt or single dad!Blaine, you can check those out.)