I'm a former moderator here at Mugglenet Fan Fiction. Now, I'm a paralegal who wishes she had more time for fan fiction. Maybe someday I'll write an alternative, Deathly Hallows compliant, ending to Do Be My Enemy for Friendship's Sake.
I would love to find a Tom Riddle/ OC (or relatively minor non-OC) fan fiction where Tom is NOT OOC (out of character). Let me know if you've read/written one. Otherwise I might have to go back and finish my own. I'd rather just read a good TR/OC than write my own--less effort that way.
(Banner by me! Want one for your story? Ask.)
I encourage you to check out the stories listed under My Favorites.
Finally! For years (literally), I've had a plea in my profile for someone to point me to a Tom Riddle "romance" that keeps Tom in character. And here it is! I knew it must exist somewhere.
In addition to the characterization, which is wonderful, I loved the references to canon. You seem to have tried to keep Tom in character, and also to have stayed true to the timeline of events happening in Voldemort's early life.
I have only a few pieces of constructive criticism. The first is grammatical. In dialogue, commas go before and after people's names when they're being addressed. Examples: Tom, where are you going? Where are you going, Tom? It's a minor point, but one that can improve readability.
My only other complaint is that the story is too short. :-) I think the story could easily become novel-length, but your profile makes it look like you're already working on a couple of those, so I won't recommend that. However, if you ever do decide to take another look at this story, I would recommend slowing down the ending. The beginning has a lovely pace--Lydia and Tom slowly, but not too slowly, earn each other's respect. The ending, however, moves quite quickly. I think the death at the end would have an even greater emotional punch if it were drawn out, just a little. I found myself wondering what Lydia's life with her husband was like. Not to mention what the impact on their child (Snape's cousin!)would be. Maybe I am suggesting a novel-length story, after all? :-)
Thanks very much for a great story!