Assalamu alaikum, I had some porn and masturbation addiction in past and also relation with a girl (not physical). It appears that her family will never let her to marry me, so I no longer kept that relation. I have broke away from all of those sins now and Alhamdulillah I've been quiet successful in this regard up until now. Though I sometimes struggle with the masturbation part.
Now sometimes I think about my future wife, like how we will lead our life, how we will have fun and also about how we will become intimate. In current circumstances of my family it's not possible for me to marry anyone before 6-7 more years, so I think of these sometimes and tell myself that one day I'll also have a happy married life with someone.
But my concern is, am I doing the zina of heart by thinking about intimacy with my imaginary future wife and is it a sin? Note that I don't think of any specific individual as I don't know who she'll be. It's completely in my Imagination. But yes I sometimes wish and imagine that her behavior and physical appearance might be like the girl I liked previously.