Marriage and last names

No, it doesn't matter where the marriage is done. Only thing that matters about the last name is who initiates the marriage interaction.
So, if you have male sim do the Get Married interaction, then the female sim will have the same last name after it is done and vice versa.
Note. The same-gender marriage is referred in The Sims 2 as joining unions and they'll be Joined instead of Married. However, this little name change doesn't affect anything at all.

So to get the last name that I want I need to make sure that I am playing the correct Sim. I have been thinking about having the wedding party at the bride‘s house because her parents have a nice big house. But I can’t do that if I want her to have her fiancé‘s last name unless I move him in with this family.

I’ve been struggling to figure out where I want these guys live anyway. Both families have home based stores. Guess it’s time to figure it out since they had a lovely dinner out and got engaged.!

Thanks for refreshing my memory!

If you're not aversive to mods, this one allows you to pick the newlyweds' last name yourself. :) http://modthesims.info/d/223528

Thank you for the suggestion however I don't like mods. I reluctantly have one (you read that correctly - ONE). It was to change about the only thing I find that makes the game not fun to play: making and keeping friends to earn career promotions, especially the one that requires 15. I hated getting THAT one but I hate more spending all day every day standing on the front lawn talking to strangers all evening while the kids aren't learning to walk/talk/potty.

It's not a problem for me on names as long as I know how to get what I want.

You can also edit their surnames in simPE if you're not averse to that :)

I know that this is late, but yeah, as mentioned earlier the location where your marriage takes place doesn't decide which sim will take the last name of the other. The factor that decides that is which sim initiates the marriage, so for example, if sim number one clicks on the alter then sim number two will take sim number one's last name and vice versa.

Okay, I've been having this problem too, thanks Mango23!