Even if it seems strange to you, this is actually quite a common request. Many women find that their partners, and even their older children, want to taste their breast milk, and if you’re okay with it, then there should be no problem.
If it’s just a taste your partner wants, then simply expressing a little milk should work. If your husband wants to ‘try’ breastfeeding himself, then you first need to make sure that neither of you have any communicable diseases, and that your baby is also healthy. This can lead to the transfer of viruses or bacteria, so you should be extra cautious.
Other than that, you’d probably be surprised to know that breast milk has beneficial properties for humans of all ages, and that it’s even been used as a treatment in adults for some diseases. So as long as your partner keeps his curiosity private, none of you have any diseases that you could pass on and you’re comfortable with it, there should be no trouble.