I am in my mid 20's and I can't get off during sex. I'm starting to worry that my girlfriend things she isn't good enough when all reality she is great. I can get off while masturbating but not sex. What's wrong?

Some men who masturbate too much have a hard time getting off during sex. You may want to try some different positions. Are you just thinking about it too much? If you overthink things while in the sack that can keep you from having an orgasm. Maybe you should try a lubricant that reacts to body heat. Or maybe you should incorporate some masturbation in your sessions. Don't finish that way- but maybe a 'warm up'.

Sounds like you have no passion.

Perhaps, you accidentally trained yourself to prefer masturbation (to porn?) to having strong emotions about your partner and making hot monkey love? :) If you accidentally train yourself to respond to masturbation only, you may be a sex addict.

You might want to consult a sex therapist to see what's going on in your mind.

That would make about 90% of all guys sex addicts if regular or frequent masturbation occurs.