Hi! And welcome!
I would suggest starting with a 'bullet' type vibrator or a vibrating cock ring.
I would maybe start giving him oral/handjob and then gently introduce the bullet into play and use it around his balls, bum and/or cock. Hopefully he'll love that (as my Husband does) and will then be able to understand the appeal.
A vibrating cock ring may hopefully benefit both of you, and you can say it's something to share.
When I first started buying vibes etc about 2 years ago, both my Husband and I didn't like the look of anything realistic (ie with veins, a head etc) so you could maybe go for something that's an organic shape, maybe have a look at the glass ones (there are a couple of vibrating glass dildo's).
If you introduce a small vibe and show how he can benefit from it and how you can have fun together and share the experience, he may go for it more.
Also, if he gets to watch you play with a vibe, he might be more open to the idea, as I think some men find that very arousing - I know mine does! If you're shy, maybe send him a photograph of you useing one?
I wouldn't get one secretly though/keep it a secret, as he's bound to find out and be more upset!
Hope that helps.