it might also be severe genital dysphoria without any other typical transsexual traits.
in many cases where people have felt extreme dysphoria over a different limb, like an arm or a leg, the only cure for severe depression has been amputation. doctors won't typically amputate a perfectly healthy limb, the persons who suffer from the dysphoria all realize what a crazy thought it is, that they would be happier without the limb, but will still often try to amputate even without a doctor's help. it's extremely rare, but common enough to have a name.
one should not easily dismiss genital dysphoria as a fascination or intrigue, just because that alone doesn't qualify as gender dysphoria. it might be just the body that is wrong, and not the social gender.
i still agree that it's important to talk to a therapist and consider all kinds of possible consequences before getting serious about this, though. complications can be bad, results can be dissatisfying, the dream may be unachievable, reality may not even start to compare with fantasy. is it still worth losing the penis (and wife, possibly), even if you can't get a vagina in its place? things to discuss with a therapist. maybe there is one out there who is open to discuss a less common form of transition.