It is not necessary to tell HR about your previous salary when you find new position.
Your new offer still is upon the marketing and your skill set.
Feel you are really po-po-ma-ma...
I got counter offer in 6 months with 15k higher than original offer after I join my current company, and got another 20k higher offer now and next week will go for it after I gave 1 month notice of leaving company.
By your situation, I would go for this lower salary for security, and later on you would have time to find new horse.
You would rather to be PM still. That is the key reason you want o stay. You take the risk as a key income source for your family.
