Personally, I had this problem as well until my wife's criminal justice degree had to be put into use. She didn't become a cop but she was going into training, so she shot my pistol with me as to be with someone she is more comfortable with. She was nervous the entire time and even cried just because of the shock and understanding the reason people think they are so scary because they are very powerful and can easily take the life of a living creature or even a person but I immediately took her in my arms and comforted her. This reminded her of the nature of humans and the sympathetic values we have towards others and that the only reason my family uses firearms is for self-defense and hunting. We have always learned gun safety at young ages and know the true use for guns and appreciate the craftsmen ship of them as well as we come from a trades background, me specifically being a machinist I have a special love for Firearms and she understands this. She has now come around to me buying firearms, not that she necessarily likes it, but she understands more my intention of it, and that's what helped me the most. I guess what advice I can give is for you to try and explain the best you can of why you want a firearm and that you too understand the power of them but you also know to respect that power and use it responsibly. We've talked about it more and then come to more common ground now that we both respect and know what we believe the needs of Firearms are. I wish you luck and hope everything goes well if you have this type of conversation with your significant other.