Thank you for your advice. I am sorry for being unclear about one thing : what he meant by that he cannot do anything about it was rather about his PE problem than his oral sex skills.

He tries to accomodate my wishes and needs regarding oral sex and other kinds of foreplay but I simply do not find it that great. The only option we have(I think) is for me to let him practice it on me (which is what I've done for the past 5 years, and yes,I gave him feedbacks during and after the act), but having to endure bad oral sex until he gets better is..well..

At least he is trying in some parts and I appreciate it, but it is just objectively not enough. I thought it would be cruel of me to blame/leave him for something he did put effort in but ended up being bad anyway