Premature ejaculation

Hey everyone!!
I'm 23 years old and I've been on a NoFap journey for close to a year now! (Other than two weeks when I slipped there was no porn and plenty of sex)
After two months of rebooting my pied healed and I was having the best sex of my life, after hooking up with several women I had a slip with pornography where I decided to take some time off without sex
It is important to state the in the beginning I was masturbating once in a while without porn and after having some issues in the bedroom again I stopped completely
I've been dating a girl for the past few weeks and we started having sex,
The first time we had sex I came very very quickly and I felt it was reasonable, because it's been a few months since I last had an orgasm, however despite having more sex I'm always cumming ridiculously fast, much faster than I used to.
I feel this is because sex never felt this good, the pleasure is too strong (and sex used to be unpleasant and I couldn't get an erection even) but now it's too much.
She has been very supportive however I feel it's a bit unfair and that I should be better.
What should I do??
I'm considering masturbating once in a while so I can last longer, however I am afraid because of my past addictions an pied.
Any advice??

 

also, something that might be related, I'm generally a fit person and I work out on the regular (I work as a personal trainer) and I recently suffered a shoulder injury that's been keeping me out of the weight room (I have been doing some cardio though). does anyone know if there can bee a relationship between the two??
(maybe because of the testosterone my body is used to from working out that I'm not getting??)