What are the reasons a childfree man wouldn't want a vasectomy?

UPDATE : SEE BELOW.

My partner (40M) and I (32F) are childfree and we were glad to meet each other for that precise point : we both consider that we can't build a strong couple with someone desiring a family. He is absolutely against becoming a father and I am glad about it, since I don't want to become a mother.

I wear a copper IUD, which makes me have 2-weeks period, because I can't take hormonal contraception (because of past health issues). The insertion of IUD is quite painful and last time, the IUD had to be removed because it moved down from my uterus, making me bleed and having acute pains.

So, one day, I asked my partner if he has never considered vasectomy and I faced a strong opposition, but no scientific reason, just that "he doesn't want it".

From my perspective, it could be a fearful move because it could impact his erectile function or something. Although, according to my male friends, it didn't affect them that way.

So, apart fearing to become impotent, what could be the reasons a childfree man would refuse a vasectomy?

Note : I respect the "my body my choice" , so I don't bother him with that topic anymore. But as a woman, I wish I could perform a salpingectomy! However, doctors in my country are opposed to it, because I'm too young.

Thanks in advance for your replies!

UPDATE : Thank you all for your replies. You actually made me want to ask him directly for additional details. He provided them : he doesn't want to do the surgery because according to him, there is enough contraception ways other than surgery. He is afraid of an surgery because even if it unlikely, It can go wrong, and he doesn't want to take the risk. He also advised me not to perform a salpingectomy, for the same reason, but he would not oppose if I end up going for it.

He is not afraid to be baby trapped in our relationship because he knows he can trust me. He tries to pick partners who are honest... But for me, you never know...

He told me that if he could wear the IUD, he would but since he cannot, he wants to follow the choice I'd make : meaning that if I stop wearing it, he would understand.

Anyway thanks everyone for your numerous answers ! 😊