I've read too much Erma Bombeck.  My first  response is "Normal" is a setting on the clothes dryer.  But that probably isn't helpful so we'll go on to my second response.

As has been said, no, this is not "normal" but it is not unusual. In some ways you have described most every family farm with a 2 generations trying to make a go of it.  You have the older generation who has been through thick and thin tying to keep it together and at the same time bring in the younger generation.  At the same time you have a younger wife who was not raised in this situation and does not understand it or how she fits in.  If you had kids it would be even more confusing.

Let's start by saying up front that one of the problems with a forum like this is we don't have a complete understanding and are dealing with limited information.  The problem is, so are you.  

If I sound a bit harsh it is because you sound a lot like a couple ex sisters-in-law. (and that is as far as I'm taking THAT!) I'm not saying you do not have valid points or that there are real concerns.  I'm just warning you I am walking into this with a different perspective than most seem to have so far.

Your in-laws apparently have a bit of a "clue" because they made hubby get a 4 year non-ag degree.   Out of curiosity, what is it in?  At the same time he apparently doesn't have a "clue" because he doesn't know how to use it.  And you have pretty much admitted you don't have a "clue" because you don't even know where your income is coming from.

Let's look at 4 things you said "The farm does pay for our health insurance and a few other things" "if I understand things right, the only time my husband has cash flow is when grain or livestock he has an interest in is sold." "that all comes to less than $15,000 a year which is not spendable income" "We live on the family farm and my husband works 1/3 of a mile down the road" Let me make some assumptions based on what you have said and my experience.

You live in a house or trailer owned by the family at no expense other than utilities and maintenance.  The farm is paying your health insurance plus some other perks plus your husband gets a share of some of the sales.

Before you think I am getting down on you too much, let me say this.  a recurring phrase throughout the Bible is "For this reason a man will leave his father and mother and be united with is wife, and the two shall become one".   Our modern mind set thinks this is all about sex. That's only partially correct.  It has everything to do with the relationship between husband and wife and that couple and their parents.  It sounds like your husband has not "left" his parents. Now, that is very difficult when you work with and for your parents.  Been there, done that, got the scars to prove it.

Your husband has to decide ... HE has to decide ... that the most important thing is his marriage. I mentioned ex-SIL's.  One didn't.  She and the kids were more important than the marriage  Time and time again we see farmers who look at the farm as more important than the marriage.  Most of them have ex-wives.

Why am I going this direction?  Because you need to understand the path you are starting down could go 2 ways.  Be certain you are willing to risk the direction it might take.

You have really caused me to sit and ponder, because I've been on both sides of your situation.  I've been the young farmer with parents who didn't understand the spot I was in.  I suspect that now I am from time to time the parent who doesn't understand the situation the kids are in.  There is no easy answer, but the first step has to be communication between you and your husband.  Something else very important is a lot of patience, both on your part and on his.

I think ... and that's a dangerous statement ... if I were you I would jut set on this a few days.  Think through some of the very good advice you've been given.  Then print this thread out and take it to your husband and tell him you wrote this.  DO NOT be surprised if he gets very upset about it.  But it can be the first step to in the communication you two need to be having.

But you have to be willing to risk which path this goes down.  Move slowly and expect progress to be slow.