Based on your facts, you both are active in the business operations, and as such, are material participants.
If you do not check the box "LLC member-manager", TT will not report the income as SE income; as you have noted in your response. This income should be subject to SE income tax and the only way to get TT to report that in box 14 is to check the box as noted above.
Don't get hung up on the semantics of "limited liability" based on your question and facts.
*A reminder that posts in a forum such as this do not constitute tax advice.
Also keep in mind the date of replies, as tax law changes.
