Seeking Sexual Advice – 21M – Why can I not last and perform as before? /u/Ok_Orange6750 Sex

Hello lovely people on the internet, I am in need of some sexual advice/guidance. I am a 21Y Male and been together with my 20Y Female partner for over 2 years now. I don’t want to waste anyone’s time with a long story so I will try to keep as simple as possible. I have always been very passionate in bed and never really had any issues with previous partners before, unfortunately I am experiencing something which I am desperately trying to fix which is how to last longer in bed (I know that this is a common question but my story is a little different from the usual). The first one year of my relationship we had great sex, the first round would almost always be a quick one but after that it always lead to 2 or 3 more that were longer and enjoyable for both of us. After the first year coming closer to the 2 year mark roughly 4 month before making the 2 years I noticed a change in how long I last and how many rounds I do with her. I always try to satisfy her and put her first, however Id like to mention that I work 10 Hour shifts and try to exercise as much as possible. With previous partners however I’ve never experienced such thing I was able to pull of a 30-40 min sessions sometimes which were great. Now however, I would go for a single round finish quick and I would feel so tired. I am desperately looking for some advice and would really like to know what can the cause of this be. If you have any questions that can help narrow this down I will try to answer to the best of my ability.

Also:
I don’t drink, I don’t smoke, I try to keep a healthy diet.

Any help is greatly appreciated, thanks a lot in advance!

Hello lovely people on the internet, I am in need of some sexual advice/guidance. I am a 21Y Male and been together with my 20Y Female partner for over 2 years now. I don’t want to waste anyone’s time with a long story so I will try to keep as simple as possible. I have always been very passionate in bed and never really had any issues with previous partners before, unfortunately I am experiencing something which I am desperately trying to fix which is how to last longer in bed (I know that this is a common question but my story is a little different from the usual). The first one year of my relationship we had great sex, the first round would almost always be a quick one but after that it always lead to 2 or 3 more that were longer and enjoyable for both of us. After the first year coming closer to the 2 year mark roughly 4 month before making the 2 years I noticed a change in how long I last and how many rounds I do with her. I always try to satisfy her and put her first, however Id like to mention that I work 10 Hour shifts and try to exercise as much as possible. With previous partners however I’ve never experienced such thing I was able to pull of a 30-40 min sessions sometimes which were great. Now however, I would go for a single round finish quick and I would feel so tired. I am desperately looking for some advice and would really like to know what can the cause of this be. If you have any questions that can help narrow this down I will try to answer to the best of my ability.

Also:
I don’t drink, I don’t smoke, I try to keep a healthy diet.

Any help is greatly appreciated, thanks a lot in advance!