Hi there,
I'm going to give you my recent expirience which will help alot.
We are in a similar situation.
I'm british but have been living with my husband in Tijuana while he crosses to work in San Diego.
We also didn't want to lie and everyone freaked out about him giving his address as mexico.
There's multiple addresses to give. We got our i-130 approved and more importantly DQed at the NVC with this.
For the petitioner we put his physical address as the Mexico address.
And his mailing address as the US address.
Having the physical address in Mexico shows that your both living together and is just the truth.
And its very important to put the mailing address in the US as it shows domicile. Which is what she will be worried about.
I lived in the UK at the time of filing so my husband had all his addresses in the US. But when working with the NVC giving address history and proving his US domicile become the most important. To back this up we sent multiple documents. (Probably overkill but it worked lol) All trying him to the US. His US bills, name on appartment, US car title and insurance, US job paystubs for 6 months, life insurance, letter of work proving he works. I think more but off the top of my head I cant remember. Oh and also we attached a letter of explanation saying he holds domicile in the US and is temporarily living in mexico and commuting in order to stay together during the wait. And that the final destination will be the US. This is essential.
I only proved it at the NVC stage but it wouldn't hurt including the letter at the i-130 stage too.
You can so do this yourself if you follow guides and keep asking questions. (And yes ownership of your house would so be enough at this stage)
Any questions let me know!