How essential is having my advisor's letter for post doc application?
I had a pretty bad relationship with my advisor for more than 4 years since I joined his lab and sometimes the relationship feels like slow inflammation that can easily flare up. We had very different opinion on how I want to approach my thesis and we argue very often on the experimental approach and the angle of attack. After that, he turned passive aggressive and completely hands-off. I noticed that he started slow to response to my email and given me very small amount time for meeting in comparison to other people in the lab. However, I proved to him that my approach was right and wrote the full paper myself and got published.
Recently, I got contact by a post doc employer who interested in my own work and request letter of recommendation. I asked my advisor for letter and he told me that I should write my own from which he can modify. I feel this is quite strange as he had wrote for all the other people in the lab, including a departing post doc who is currently interviewing for job. He told me he had done the same for other people but obviously he lied to me.
I further asked if he can provide me a copy of a completed version of the recommendation but he refused.
My question is should I still trust him to write my letter and is it essential? This post doc position is a great opportunity for me and either way I do is a big gamble.
Update: I decided to let my advisor wrote a letter for me and I think I may have made a big mistake. Since he wrote my letter, I asked the post doc lab head if my letter is completed and I no longer be able to hear back from him. Before that, he was quick to response to my email and showed great enthusiasm. As an insurance, I use one opportunity I have less desire to as bait to test the water and I still have one more shot at another position I really want. Now, I'm thinking requesting open letter from advisor from now on for any future position or use letter service to check the letter.
Any suggestion? Thanks.
update: Great news! Got interviewed and offered at top ones! Thanks everyone!