Church wont let me serve

This makes sense. 

You are not a member. Only members participate in serving in a church. It is why you need to become a member. It is about accountability and responsibility. They cant have people, by policy, running around helping when they dont know if that person is saved. Today theres far too many false converts in the church, who snuck in since 90s and found their way into leadership positions, and bring distruction. 

This church has a way to try to protect against unsaved in serving, and being looked up to by congregants, and from leadership positions.

Today, they run background checks on members since all can and are to serve. They cant let a pedophile or rapist, or male sexual predator, or drug dealer, or progtessive, be serving in church & influencing or harming pthers. They also need parameters and safety for congregants. Too many today claim to be saved but theres no proof and no fruit in their lives. They may only know you 4 months or 2 yrs and that's not enough time to know if you really are saved and living righteously. They need time to be in your life to see that. And note, they can kick out non members for sin and issues just like with members. So it is to your benefit to just join. 

So if this church holds "the essentials" of Christianity, and you are saved... join that church right now. So they can intertwine their lives closely with yours in fellowship (in & outside the church) and so they can then find places you can serve, once they have watched you enough. 

If it is not a biblical church, flee from it! Idc if your fiance goes there. You do not want to join a cult or false church. If the fiance loves you, he will go to a biblical church with you, even if his entire life and family were at that other "church". Do not get sucked into a modern cult. Stand firm

👉If he doesnt love you, leave and live in peace and truth. You dodged a huge bullet.