Good Morning Paulie,
If you do not mind I will give you what I get from the dream. If you do not agree with my analysis. It is okay. With that said, here goes.
Death represents many things in dreams. Not necessarily death. In your dream, the figure represents PAST. Past interactions, sensations, etc. that you were comfortable with. It also represents what you have told yourself is no longer "okay" since you're now married.
The sensation/ fantasy presenting itself as a DARK figure indicates in your subconscious you do not want to be okay with this. If it was something you weren't trying to suppress or leave behind it would present itself in another way. It would've present as someone you saw, someone you know, a celeb, etc.
To deal with the dream presenting as a dark figure you will have to process the sensation, why you're having these thoughts, and what you will do about them. Ironically you're fueling them in a sense. Do your wife know about the pornography? I'm sure she does'nt, hence it is a secret (darkness). So they fantasy will continue to present itself as a dark figure. It is a possibility these thoughts represent death to your current lifestyle. Meaning the fear of losing your family or reputation. (something to consider
Time to bring some light into the equation. Discussing this with someone. A friend, counselor, spiritual leader, your spouse. Expressing your truth, no matter what it will be.

Hope this helps some. Be well.

Belle