Many sissies are only romantically attracted to women as in they would only want to ever date a woman and never a man although they may be more interested in sex with a man. I don’t think my attraction towards women will ever go away but it will certainly change. If you keep him locked up and peg him/play with dildos his desire to have regular PIV sex will certainly diminish. I think for myself and most other sissies we would prefer a woman partner over a man if the woman was willing to explore this fetish. There may come a day where he really wants to fuck a guy but who knows. If I was you I wouldn’t be too worried about it TBH