Observing purda form one aunt's husband

I am a young women, ready to get married. I studied kitaabs for four years . My predicament is as follows: I have an aunty (mothers sister) who stays quiet a distance away from my home. However from small I used to go and stay with her during the holidays. Over the years we have created a strong bond between myself and her family. We are so close , I can consider her as my second mother . After all this said, my story is with her husband. He is about 37 years of age. I find that over the years of staying together we have become very casual in our interaction. We laugh and joke around freely, sometimes he even touches me and vice versa. Taking into consideration all the above factors, please advise me.