I understand where your husband is coming form (having to worry about 2 mortgage payments but if you can show you have enough reserves that should enable him to move forward). 

At the same time, you need to meet your living expenses and hopefully build up some cash which will enable you to take risks when you are ready and capable. 

Through various court battles and decisions, Jerry established the principle that due-on-sale clauses were an unreasonable restraint on alienation of property and therefore unenforceable, thereby enabling many sellers of homes to retain their homes and sell them, rather than lose them to lenders in foreclosure. 

It has something against it (aka collateral), especially as I have 30%+ equity in all my properties which should - barring the end of the world - enable me to get rid of all debt if need be .

since the issues needed to be  addressed in any sale (whether it be to me or someone else),  The bank paid to fix the structural issue prior to closing, which enabled the building to be insured.  

Native apps (meaning the BiggerPockets apps on the Apple App Store and Google Play Store) allow us to build free of the constraints of the technologies available in web browsers, which in turn enables the resulting app to be faster, snappier, smoother, more responsive and generally nicer to use.

Any shortfall would be my “investment” to enable me to qualify for a mortgage sooner rather than later, which might be very well worth it for lifestyle improvement.  

There are many factors that will enable you to do this including how much money you have to put down and how much your property will command in rent.  

I really like that apps have email addresses to enable integration, for example Vumber.   

Has anyone built an excel spreadsheet that enables this type of analysis?