Wow, Christmastime and birthdays must be stressful for you guys!
I bought myself a Fleshlight while my girlfriend was out of town for a while, but I can tell you that there is a sort of odd emotional dynamic when it comes to these things. I'd absolutely prefer anything she does over using the Fleshlight, but sometimes she's just busy, or menstruating, or out of town.
The thing with your men here may be that they feel as though you're buying the Fleshlight because you don't want to be bothered with them. If my girl was like "hey, look, I bought you this: now I don't have to worry about getting whiplash once a month", I would not have a favorable impression of the product either. Still, if you treat it like a couples' toy, I don't see any reason he ought to be against it.
There's also a sort of machismo tied up in it. Some guys might think it's weird or pathetic to use something like a Fleshlight, and there's really no getting around that. Still, if you make it about you, and tell him it's something you want to try because it turns you on, he might open up to it.