Messianic congregations are not a unified entity by any means, so it depends entirely on the individual congregation. A few are doctrinally sound, many are not. Many may seem to look good on paper per their Doctrinal Statements but either have *code words* that the uninitiated do not yet realize or the actual teachings or body life of the congregants to not bear out what they say they believe. Many, many believers who have started out in the Messianic area moved on into the Hebrew Roots cults (there is too often a blur between the two) - we know this by the testimonies of the ones who got out. Some do not get out; they become so enamored of *all things Jewish* and are fed a diet of Judaism, the Law, the rabbinical teachings from anti-Christian (and Gentile!) teachers, etc., that they ultimately deny Jesus and live as Jews.
Be careful.
I'm curious as to why you would refer to one member of the couple as an "ex-Protestant".

I can understand the not wanting a label of a denomination as a self-defining thing, but are you saying you do not hold to Protestant theology? How would you describe the beliefs then?
This raises a red flag for me because it sounds like a couple who may be ripe for the very subtle and cunning lures of the Hebrew Roots/Messianic aberrations. If you are not
very strong in your beliefs about the absolute and total grace of God in our salvation and in our sanctification, the "Hath God saids" of temptation to spiritual adultery can be very powerful.
Some good stuff here, wrapped up in the Conclusion:
http://joyfullygrowingingrace.wordpr...ement-so-what/