I agree with this.
Wanting something does not mean that you are in a position to have it. Find out what his reasons here are, and do so honestly. Do you have the space, the money (without sacrificing savings, your future, or going into serious debt), the zoning, the ability to get care for the animals? What are you going to do about vacations with these giant reptiles? Who's going to care for them? What is the money you're going to spend on them NOT going to be spent on instead? where is it coming from in your lives (and it is coming from somewhere - what AREN"T you going to be buying, doing, or saving because of this)? What about your relationship with other people/family? Will he lose friends to this?
If you have a life with someone, your dreams impact them in big ways and dreams as big as giant reptiles come with big sacrifices and lifestyle changes. "If you loved me you would" is an emotionally manipulative jerky thing to say. It's no more valid than 'If you loved me you WOULDN'T."