I think he would certainly be considering it even if he does not have the bottle to go through with it.
My interest in Shemales was only possible due to the internet so it was a fairly recent thing. For years I had fantasised about being fucked by another guy and always wondered what a cock would taste like.......it remained a fantasy for a long time because basically, I'm not gay (and I have a brother that is, so its not as if I can claim denial at this late stage
), blokes just turn me off and for ages every time I tried to imagine a situation with a guy it was just like urgghhh.
So, like your relationship we turned to trying a strap on........trouble is, its not part of a woman and woman really cant use them as a guy would. Many guys like anal sex, it's nothing new.
The thing is, Shemales are something new, they look almost like women and some are truly stunning in the male eye. The only thing that sets them apart is the very thing that attracted your bf to a dildo.
In the end I went to a shemale escort and decided not to tell my wife........just a step too far in an otherwise totally open and trusting relationship. If you are really, really open minded then you might consider bringing a Shemale into the bedroom with you (not many Shemales are up for that so it might be difficult to find one), in the end you would be bringing a good looking male into the bedroom and not a biological woman......weird huh, he thinks he is getting a woman and you can see it's a guy. I dont suppose he would go along with you suggesting that you fancied a threesome with another man, but that is exactly what it would be.......I reckon if you suggested it he would be very shocked, but at least you would be giving him the freedom to choose, if he said 'no way' you know where you stand.