It's hard to provide an accurate answer without more details. You split expenses? And you have $1.6M in retirement is that joint, or in just one of your names? You have $290K in your name in a taxable account? Does your husband have his own taxable accounts as well? Is the $80K-100K you want per year for the both of you, or just for your part of the expenses?
If you're asking whether you are in a position to take 3-6 months off to figure out what comes next, then yes, absolutely -- you have $300K in taxable investments and cash, which can clearly cover your worst-case expenses of $6K/mo. for 6 months. The problem is figuring out what your options are after that time -- you've got another c. 10 years until your DH hits 60, so how are you going to cover your $4-6K/mo. share until then? Your $300K will cover several years of that, but not the whole time, and how long that will last will depend in part on what your share of the expenses settles out at after you quit.
