Refractory period can be a b****h....
There are
Tantric Exercises one can do to extend one's duration. I have no idea how well those will work with this particular issue.
Perhaps you can offset your early arrival to the destination by applying a bit more oral to him prior to his doing anal? Get him closer to his destination thus he arrives near or around the same time?
For myself I know that the only way I can arrive is missionary style (me on my back, them on top) Doggy style the angle of attack of the penis isn't rubbing as hard on the prostate.
There are numbing creams/lube - but I assume that they would numb him as well unless he is wearing a condom.
My first partner did 'exercises' with me. He would 'lounge' on the couch - not actually laying down, not really sitting, feet on the floor, head on the back of the couch. He would have me sit on him, lean back against him and 'relax' and then he would tease me and torture me as I sat on him. Its called
Orgasm Denial.
He managed to get me to require more of a journey before arriving at the destination - if you know what I mean.
If your prostate is too sensitive, there may be an underlying medical condition. Prostate infections of the low order sort can lead to hyper-sensitivity that can lead to early ejaculation. Those usually progress to pain and discomfort during sex, but initially they can be quite 'pleasant'.
Most partners have a timing issue - one arrives earlier than the other, it takes a while to learn how your partner is feeling at any given moment. Thus the best thing may actually be to communicate and learn how each other is actually feeling each step of the process and to adjust the activity to suit.