"My girlfriend wants me to change my religion for her in order to get married but Mormons are weird. I really like this girl but don't want to have to wear funny underwear for the rest of my life or give up drinking. What do I do?"
All religions are weird if you don't grow up in them. Think about what Christians believe if you just heard about Christianity. "So you believe the Son of God was born in a manger to a virgin two thousand years ago? And that this dude named Jesus rose from the dead three days after he was crucified and ascended into heaven?"
I mean, let's just take a step back and pretend that one of your buddies came to you and said, "So I'm dating this chick named Mary and we've never had sex before, but she's pregnant now and she claims she's still a virgin and that God made her pregnant. And I totally believe her because she would never lie to me. Should I stay with her?"
Every single person reading this would say no, right?
Yet that's what happened to Joseph according to Christians. And everyone who is religious will get mad at me for saying I think it's way more likely that Joseph and Mary were playing just the tip and Joseph got carried away and then later they decided to say God got Mary pregnant.
Forgive me for being skeptical, but I'm just not buying supernatural pregnancies.
My point is simple -- all religions require crazy, illogical leaps of faith.
The crazy thing about the Mormon faith is it requires all these leaps of faith to happen AFTER AMERICA BECAME A COUNTRY.
George Washington is older than Mormonism.
So, anyway, if you really love this girl you become a Jack Mormon. There are plenty of people just like you, Mormons in name who continue to do non-Mormon things. For instance, you can still drink, not wear Mormon underwear and drink caffeine and call yourself a Mormon.
I'd be straightforward with your potential partner, tell her you're fine with changing religions but you aren't going to change your behavior when it comes to alcohol and underwear.
If she's not okay with that and you truly aren't willing to budge either that's fine, but you guys need to break up.
You could also do what most people do when it comes to religion, say you're religious but only so you get more likes on your Facebook posts. Hell, this got Trump elected President. It's not like you have to pass a test. (Note: you may have to pass a test to become Mormon, I have no idea. And if that's the case there is no woman alive I would study to pass a religion test to marry. Not one.)
I would, however, be fine doing what most people do when they change religions -- don't change your life at all but announce you're now a new religion.
At least that's what I did when I became Muslim. And if there's one thing I've learned since then it's that most Muslims are very easy going and don't take their religion that seriously.