When we were young, we got a nice windfall, we used it to pay down debt. It made such a difference in our lives not to have those cash flow issues. We took the payments that we had been making and moved those to the house and savings. Before I was 40 the house was paid for, and before I was 45 we had college tuition for two kids still in middle school in 529s.
We have a mortgage again. We took it out to help my brother in law who passed away last year by buying a second small house. This summer we sold the house. I could have paid off the mortgage, but I decided to keep it. The mortgage is small, and I know that I want to finish my basement at some point in time, so I want the cash on hand and don't want to be at the whim of the market (where most of my money is tied up).
In the meantime, I've been pretty aggressively paying that mortgage.
I'd talk to a financial planner - like you intend - and map out your long term goals. Being a SAHM is expensive in terms of loss of income - and you'll want BOTH savings and cash flow to support it. You have a lot of debt other than your mortgage that I would make a priority - unless you have a lot of other savings or some other sort of safety net, leveraging debt to make money isn't a great idea - and my suspicion is that you aren't there yet. If my suspicions are true, if you invest that money you could find yourself in a situation where you are home with a kid, the market crashes, your husband - whose job is dependent on the market - is either out of work or not making much money in a panic, and your nest egg is worth half of what it was - with the debt and cash flow you have now. However, I could be wrong.