"If I imagine my wife as a sexy model, and that's the only way I can be intimate with her."  So imagine away.  Why not?  What's the harm?  At this point, you are wanting/craving/needing sex.  Better with your wife than the stripper.  And maybe the sex will bring back some feelings & some sort of connection.  Maybe I'm way off, but I see no harm in it at all.  I know with my husband & his d, sometimes the sex was the only connection we had...& that was okay with me...it was what he needed & what he was capable of at the time...and I liked the intimacy & the connection as well...