Interesting story, certainly. The only problem I have is with the amount of spelling mistakes and grammatical errors, such as misplaced commas, capitalization of words that don't require it or a simple loss of a period at the end of the sentence. Other than that, I believe your story has great potential and wish you the best of luck with it :)
I like Tristian I think. Love the updates by the way!! Going with Tristian, I think would make it more interesting. Update soon, I can't wait to read more. (If you go with Tristian, make him work for it!) =)
The reason I think Tristian would be better is because of the fact that he was always there. In his ways he thought he was protecting Venus from the beginning. There are moments in the flashbacks that you write were you think "they were made for each other". You can tell that Tristian likes her a lot but he was shaped so much by the pack and society that he doesn't really know how to tell anyone or her, that all he can do is be a bully and outcast her to try and protect. Henry doesn't seem like a good fit to me because to me he like Venus for the "lack of wolf" aspect. She's not aggressive like the others, she automatically disliked him because he killed her father figure, and she is his little brother's best friend. Henry is kind of like her "Guardian Angel" instead of "soul mate"