Everything is in the title but in case it matters here is some context:
I don't fear things (spiders or snakes or blood or needles or whatever) and I don't really understand how/why people are afraid of those things.
My BF on the other hand IS scared by some things.
A typical example is needles: I donate blood and he agrees with me on how important it is, but he never joins me because of his fear of needles (he sometimes comes but doesn't stay with me while they take my blood). He WANTS to, but he can't (I have never pushed or pressured him about it, he genuinely wants to do it, because he thinks it is the right thing to do).
So our problem is: Sometimes we/he can't do things we/he WANT to do because of fear.
I do understand that fear is not something rational and I'm talking about fear of things "you can touch" (like animals, object, not fear of dying or fear of heights or fear of accident/car crash).
What I have tried so far:
Being rational about those things: He agrees, but it won't go further (OK the spider won't eat/kill me but I won't touch it anyways (I still need to be around when there is a spider in the house))
Work on the origin of fear when possible (worked pretty well but not always applicable; sometimes there is no rational reason behind the fear or I just don't get/know where it comes from)
Being pushy and show him afterwards "See it wasn't a big deal": Kind of worked once for a small fear, didn't worked AT ALL for a bigger one - I won't try this again
Be an example: Same as number 1. He watches me deal with the thing, says it's OK but it never goes further.
So the main question is:
How can I help him overcome his fear? (When he wants to get over it or at least want to do things even if he is scared. I won't try to help with a fear he's not ready to face.)
Subquestion: How can I have a better understanding of his fears wich may allow me to help him?
Edit 11/01/2018 :
To those saying that these fears are minor and we can live with it : Yes, I agree, we can and we do. But there is plenty of them, some that he wants to get rid of and some that really annoys me. Main goal is to help him with those he wants to face and maybe later when he'll be over them he may want to face those that annoy me or I can gently convice him it would be good to work on them. I/We need advices because it will improve some/a lot of stuff in our life if we manage to deal with some fears, but if not we won't break up over it.
I'll take a couple of hour to process every answer and I'll follow the advices about exposure, and taking small step (and not mothering him too much) and I really appreciate the time you took to help me. Thank you all :) I'll accept an answer soon (a lot of good answers !) and I'll try to come back in a few days/weeks to give a feedback on the situation !
Again thank you all !