I don't think that a problem with sex is ever due entirely to one person... it is an 'our' problem kind of thing rather than a 'your' or 'my' problem kind of thing.

I think that the solution might lie in comprimise... Could you talk to him again about whether maybe he thinks that he will lose his erection if he holds off for a little longer? His reluctance to wait might be due to that and his fear that if he loses it that won't be satisfying for either of you (and will be embarrassing for him)... Or he might be concerned that he doesn't have sufficient control over the timing and that if he tries to hold off that he will ejaculate kind of inadvertently and that won't be satisfying for either of you (and will be embarrassing for him)...

If you can reassure him that you are up for a bit of experimentation and that if either of those things happen then that is fine - just par for the course in figuring things out... Then he might be up for that.

Similarly, could you talk to him a little about alternative things you could do together before penetration that might make it more likely that you won't need as long to build up to climax? It might be worth experimenting with altering things in both of the above ways in different combinations (at different times or at the same time)

Variety is the spice of life :-)