The subject of comparing affairs to gambling and drug addiction are documented in the description of cluster b personality disorders as well.
For my W, she's a recovering alcoholic and has relapsed to a degree; she loves to gamble; cannot manage money; has no impulse control; and seems to have a sexual addiction. She cannot seem to make the connection that love is not sex.
After she dropped the bomb, I had her texting restricted. The restriction hit at 1:20 am while she was at some club. During the heated convo (she was the only one heated) she mentioned that she loved me and I told her that I loved her; but immediately she went into a diatribe about how she didn't want sex with me. I told her my love wasn't about sex; it was care and devotion. That's not the only time she's said that.
I really think that in some people there is not capacity to feel nor give "true" love. For my W, it's a feeling and the act of sex.