Need to close or open a circuit (and keep it that way) with magnet
You could use reed switch output to toggle a flip-flop such as a 74LV74. 

Simply connect the /Q output to the D input and the clock input to the debounce circuit output. /CLR and /PRE must be tied high (along with any other unused inputs from the other half of the chip). 





The Q output will go high and low alternately each time the switch opens. It will not start up in any particular state, to do that requires a bit more circuitry and the use of the /CLR or the /PRE input. 

Do not substitute a flip-flop that does not have a schmitt trigger clock input or you may get false operation.