HappyToPE, your tool is already pretty huge, guys with below average dicks that are doing this come from a very different place than you, and the information that they PE could be used against them.
For you, it can’t really be used against you… ie: After you break up and your girlfriend is gossiping about you, all she can say is “He is really hung and he does exercises to make it harder and bigger, I feel sorry for the next girl he gets with, having to take such a big penis!”… All the girls giggle and imagine being that next girl …
For the guys with small ones the ex gf gossiping with her girls says, “He has a small penis and is so insecure about it he actually spends an hour a day pulling it hoping it will get bigger!” … all the girls laugh hysterically at the poor guy.
So if you really do feel the need to tell your significant other I would definitely focus on the exercises improving EQ and stamina, tell them they are exercises for sex just like any athlete would exercise his muscles for the sport he plays, its like kegeling for girls, your girl does kegels, doesn’t she? …
I would NOT tell them you are doing it because it might increase your penis size, if they do notice gains after you have told them about your penis exercise program then you could say, “Its probably a side effect of the exercises, I’ve read it has happened to some guys”. Also, what happens if you are a slow gainer, or one of the few guys who never gains anything, then your girlfriend will see you as a failure, which is never good for a relationship.