Reach on free strikes

for example i end my jack has reach and oponent doesnt i go and attack him leaving a 2inch gap
now that warjack doesnt have reach walks in and hits me do i get a free strike ??? he isnt leaving my front arc and i engaged him first

Please read the Free Strike rules again. Often, a rereading of the rules will clear up questions like this.

Short answer: No.

Long answer:
Your model only gets a free strike if the enemy model that your model engages leaves your model's LOS or melee range.

Do note that even if your opponent has a shield (0.5" melee range) and a spear (2" melee range), you only take a free strike if you leave his 2" melee range, NOT his 0.5" melee range.

oooo thx