I need your help, I don't know if I am normal or if I have a physical or psychological problem.

I can take hours to cum during sex, and cum in minutes when I jerk off by myself.

I feel like I have a curse and a blessing at the same time. First, I'm always willing to make my partner come first, but it can be frustrating for my partner not to see me come. Also for me I would like to feel the orgasm when I fuck.

More details and food for thought :

I don't know if everything is relevant but I'll give you some info and let you make your theories:

I am circumcised, my dick is about 20 cm.

I jerk off in a very specific way, with a plaid/fluffy blanket wrapped around my dick (this method makes me cum very quickly and I'm much less sensitive when I just jerk off with my hand even if I still end up cumming)

I always jerk off with the same hand

I jerk off almost exclusively to video or audio porn.

I rarely cum during the act without any intervention from me, but it does require extreme concentration from me for several minutes where I close my eyes and concentrate on my pleasure.

Also cumming when I am standing or otherwise than in bed can be complicated.

I am bisexual and I have this problem in the same way with women as with men.

I also have the impression to be less sensitive of the cock than many people, I feel pleasure but I have the impression to feel less than others

My theories are:

That I put too much pressure on myself to please the other person that I forget to relax.

That my very specific way of jerking off makes it very difficult to cum in another configuration.

That I have a psycological problem

Maybe an addiction to porn

Or simply that my cock is just broken.

Need your help and advice.