There are two types of Taqiyyah:
1) Taqiyah is done for safety reasons. For example, a person fears that he might be killed or harmed, if he does not observe Taqiyah. In this case, it is obligatory to observe Taqiyah.
2) Reconciliatory Taqiyah. This type of Taqiyah is done when a person intends to reconcile with the other side or when he intends to soften their hearts. This kind of Taqiyah is permissible but not obligatory.
None of the above seems to be your case. I strongly advise that you build your relation with your in laws with 100% transparency. It guarantees sustainability. You should have courage to defend your faith and love together.