The particular verse you reference reads as follows: And so I [Jesus] say to you, whoever divorces his wife (unless the marriage is unlawful) and marries another, commits adultery. (Matthew 19:9) 
 
The phrase, "unless the marriage is unlawful" is from the Catholic New American Bible, and is a rendering of the Greek (me epi porneia) which most literally means, "except for illicit sexual union". 
 
The Greek word in question is porneia. This word refers generally to any illicit sexual union. Depending on the context, it most often means premarital sex, but can also refer to incest, and more rarely to adultery and/or homosexual acts. I say "more rarely" because adultery and homosexual acts have their own proper Greek words and descriptions that are normally used (e.g. Moichao (adultery) and paraphysin etc., for homosexual acts). 
 
Some, especially from the Protestant tradition, think porneia, as used here, means “adultery.” Hence, they hold that divorce and remarriage is allowed if one (or both) of the spouses committed adultery. But this seems unlikely, since, if the Lord meant that, he could have used the more specific word for adultery (moichao) which he uses later in the very same sentence! It also seems a strange logic that one can avoid a second marriage being considered adulterous if the first marriage is rendered adulterous by one or both parties. 
 
Catholic teaching and understanding regarding the word porneia holds it to mean in the context of this verse, “incestuous relationships.” 
 
This makes historical sense. The Jewish world had very clear understandings about permissible marital unions, forbidding marriage where the bloodlines ran too close, e.g. siblings, first cousins etc. But as the Gospel went forth into the Greek and pagan world, there were differing and unacceptable notions about who could marry who. 
 
Because of these many strange marital practices, the so‐called Matthean exception seeks to clarify the Lord’s teaching. Thus, the phrase “except for unlawful marriage” (sometimes also rendered “except for unchastity”) clarifies that those who are in marriages that are illicit, due to incestuous and other invalidating factors, should not stay in them. Rather, these are not marriages at all and can and should be set aside in favor of proper marriage.

Drinking water does not break the fast before communion. The current rule, in place since 1964, says, “A person who is to receive the Most Holy Eucharist is to abstain for at least one hour before holy communion from any food and drink, except for only water and medicine.” (see Canon 919). 
 
It is a bit odd for a liturgical minister to be drinking bottled water in the Sanctuary. Perhaps the deacon has a health problem. But, precluding that, one would think it was usually possible to go without water for an hour or two. Water bottles are a kind of modern fad. We used to manage quite well without them.

You describe a difficult situation faced by many today. A brief column such as this cannot explore all the moral issues involved here, but the bottom-line answer is, no, you should not divorce. 
 
The well-known axiom that the ends do not justify the means applies here. And while the “end” of trying to save your money, presumably to give it to your children, is a good and understandable end or goal, one cannot sin in order to obtain it. 
 
What is the sin involved in what you ponder? Fundamentally it is either to divorce, which God hates (see Malachi 2:16) or it is to lie. 
 
Regarding divorce, it is essential to recall the vow you made which is very pertinent in exactly the case described here. The vow said, “I take you to be my wife, to have and to hold, from this day forward, for better, for worse, for richer, for poorer, in sickness and in health, until death do us part.”: Clearly sickness and poverty were anticipated as a possible scenario in the vows you both made. 
 
But one might argue, “We are not really getting divorced, it is just a legal move regarding civil marriage. We will still consider each other as spouses.” But in this case, a lie is being told to the State for the purpose of Medicaid funds. 
 
Either way, it seems that what is proposed is that one do evil (sin) that good may come of it. This is not a valid moral solution to an admittedly difficult and painful issue. 
 
In recent years, Long Term Care Insurance has been a solution to some of this, but for an older person, this new device is seldom much help since, if they have it at all, the premiums were high and the payoff low. 
 
I pray it might be of some consolation to recall that the goal in life is not to die with a lot of money in the bank. The goal is to die in holiness. God has promised the Kingdom to those who are persecuted for the sake of righteousness, and who have done what is right, even at high personal cost.