Does God Discriminate?

I'm having a really bad day. This whole "getting married in a church" thing has me down and out. Because...

Fiance's family is devout Catholic.

I am not. I don't have an affinity for any religion, whatsoever.

Here's the dilemma. Mom-In-Law really wants us to be married in a Catholic church. Being the fantastic daughter in law that I am, I really do want to respect her suggestion.

But.

This Catholic thing really, really bugs me out. Three reasons why:

1. We would have to LIE to a church in order for them to marry us. Who wants to start a marriage based on lies?

2. We most likely have become a member of the church we're married in. Uhm, I'm not a member of any church, nor do I intend on becoming one.

3. If God does not discriminate, then why do Catholic churches turn us away when we say:

A) I'm not Catholic and
B) We live together?

That's all.