Welcome here to the forum, it is a most perplexing problem, and sounds like an irrational extreme fear of spiders has spilled over into an irrational attitude towards you. Very upsetting indeed, leaving you wondering how the relationship will survive.
I guess there are several problems to try to deal with.
The first and most obvious is Cris' very great fear of spiders, something that is making a huge impact on his life, and and indirectly on yours.
May I suggest a two pronged approach? Just for the moment sacrifice the spiders, as you did that last time, but dispatch them humanely in a way that Cris knows you are going against your principals, but are doing so for his sake
At the same time encourage him to seek medical help -a deal if you like. There getting a GP to refer him to a a psychologist or clinic that can treat this excessive fear, something that can be successful, but might take a while.
This can be a pact between you, your putting aside your feelings for living creatures provided he does his bit and earnestly seeks help -and sticks with it. Such therapy is not onerous or frightening once it is explained by a professional, quite the reverse. You are not asking him to do anything stressful.
It is fair to say that many have such a fear, though to a lesser extent, also that Cris may have encountered perilous situations in his home country that have made the fear worse.
Your post is not long, it is clear and sets out the problem well. Having someone to love, and being loved in return is infinitely precious, and worth effort from both of you.
I'd be grateful if you came back and said what you thought.