How to quantify added value of renting to my ex-wife?

[David J Carciere]

Hey BP

I'm looking at a duplex and trying to figure out if it's worth moving forward on. It's a quality asset, great location, units generally in good shape, although there is some value add (forced appreciation opportunity), the only downside from the  typical model is I don't think it can get bought at much of a discount, certainly not a 20% discount.  

The potential upside though is If acquired, my ex-wife could move into one of the units. We get along really well, so I'm not concerned about her being a tenant, and I'd be happy for her and our kids to have a safe, secure place going forward. However, I still want to make sure the deal makes sense. 

As part of our agreement much of what I pay her goes to her paying rent on her current place - obviously if she was a tenant of this duplex that money (that I'm paying out anyway) would be going directly to my own mortgage.  

Is there a way to quantify the value in that, is it as simple as over "x" number of years, my mortgage will be reduced by "x" number of dollars that essentially I'm paying to myself as opposed to another landlord? Or is it really no different to have her in there than another tenant? 

It seems like it's better to be paying down my mortgage on an asset I own, rather than it just going to rent somewhere else, but maybe not?  

I guess to bottom line it, I'm trying to quantify assuming this duplex can't get bought at a discount, how does that compare to the value of money I'm already paying out going directly to pay down my mortgage.

Hope that makes sense, kind of personal, but trying to look at it pretty quantitatively. 

Thanks for any thoughts!

David