Some numbness, gradual loss of erection, long long time to O

Ok here's the situation. I'm a 39 year old male. Divorced, various flings since, with long dry spells in between spent masturbating to porn. I think I developed some dependency on the porn, because when I do have real sex encounters, I'm often somewhat nervous about performance.

So recently, much to my delight, I began dating a 30 yr old hottie. I now have the opportunity again to have great amounts of wild sex.

However performance wise, things are problematic. It takes me a long, long time to reach orgasm, and I can only get there by rigorous, fast, rabbit humping. Or, I gradually lose erection, become discouraged, tired, and just cannot ejaculate at all.

I actually feel really close to this girl, and we have a great sensual connection. But the gently rhythmic kind of lovemaking just won't get me there. I end up pounding her (she seems to like it) with urgency to just please be able to ejaculate and not go soft. Same thing happened with a previous fling. The sex is great but I would love to be able to slow it down, experiment, etc, without worrying about going soft and tuning out.

Even when I feel super horny and lustfully initiate with her, I still eventually lose the erection and my drive. (Or again I need to pound relentlessly). I have kinky thoughts all the time, often crave sex, but once I reach the actual sex, it falls short of the fantasy. It seems like truly a sub-conscious part of my brain. I don't think I can just consciously relax and solve this. I believe, I hope, this is just a conditioned dependency from the porn.

We like to wine and dine together, but with any alcohol it's even more hopeless.

Viagra might be an option. But once it keeps me hard, I still need to reach ejaculation which is different from just being hard. I still have to pound relentlessly. This is all very frustrating. Recently I started taking 500mg arginine, but no conclusion yet. I take some fish oil and tyrosine also.

Is this the kind of thing that will gradually correct itself? Are there any exercises I can do to get back to normal sensitivity? (if that's what to call it).
Thank you for any comments.