You know, I wouldn't do it. Because a lot of chancy things have to happen and a some money has to be spent before a mare and some frozen semen produce a foal. Plus, a foal can be lovely and healthy, or it can be aborted, or worst case scenario it can be a terribly sad and expensive burden. (And FYI, nothing turns a SO more against horses than learning about how sad and expensive it gets when things go wrong with them, especially broodmares and foals.) Keep in mind that a proven mare plus a few doses of frozen semen might = a mare and foal a year down the road, but a proven mare + few doses frozen semen might also = proven mare + $5000 in vet bills and no foal.
I'm not a marriage counselor, but I've bred enough horses to know that this is not the kind of gift that is likely to strengthen a marriage.
welllll, I guess BeeHoney has a point, but if he's already interested, he might be excited to have the opportunity to do it for himself.
it sounds to me like if she already has a mare and the semen, discussions as to breeding have already been had, and perhaps he's shown a desire to be more on the inside, rather than the outside looking in??