Delayed Ejaculation

Hi there,
I'm having a problem lasting too long during sex. I've done a little research into the matter and think it might be delayed ejaculation. However, the cause probably isn't psychological as usually mentioned. It's definitely from the fact that I was masturbating regularly for about 10 years without having sex. I notice that when I masturbate, I usually apply more pressure (squeezing my pointer and thumb around my penis ) and move my hand extremely rapidly back and forth. I usually only focus on the tip of the penis without going lower than where the shaft and penis glans meet. In the past I never thought twice about it; I found an extremely pleasurable way to ejaculate. However, now its interfering with my sex life and I'm not too happy about it. I've tried masturbating more normally now but with little success (ie. slower, less pressure and fully up and now the shaft). Is there any exercises or ideas from experience or knowledge that anyone knows can help my situation. It would be greatly appreciated.

Also, on a side note, I'm not sure if I desensitized the tip of my penis by masturbating that way. The connection of the tip to the shaft doesn't seem very strong. I can usually move the tip up or now fairly easily during an erection. Any thoughts?