Peyronies disease is basicly scar tissue replacing the internal penis tissue and therefore causing the bending.
If we are talking about a state that doesn’t involve Peyronies and it has been like that as long as you can remember, usually your other half has simply developed better, mayby because of restrictive clothing causing lower blood circulation on the other CC in your childhood. Also this can be caused by jelqing, even though it’s a rarerity. Some have had good results in correcting by jelqing against the curve.
Note that possible causes can also be some kind of injury, Vitamin E deficiency, use of beta-blocking agents, autoimmune phenomena, any kind of penile surgery, tear in the tunica, etc…
"Be aware that there are several schools of thought here as well. Some seem to go with the hard and heavy approach. The sessions are brutal. You can hear them talking to their dick: You better grow mofo or I will punish you even harder tomorrow! Others seem to favor a more tender approach. Always listening to what their member is saying while massaging it gently and singing to it with a soft voice. If it is moody and not happy with new behavior, they always listen and are very understanding."