First, be sure to check the "60 and Over" board. This topic comes up a lot there.
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Many Providers who post to TER say that they know about ED, are understanding, and some have methods to help. (Some prefer to try a cock ring or other methods.) As you inquire and communicate on the boards or in private, you should get some good suggestions regarding (a) Providers in your area that are good with ED issues and (b) techniques to try and (c) ask your doctor and urologist for diagnosis and treatment suggestions.  
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Some might suggest that this thread be moved to 60 and Over. I'll leave that to others.

"Baseball is 90 per cent mental. The other half is physical."  
It's true about fucking, too.
If you worry too much about it you've already lost the game. IOW, it becomes a self-fulfilling prophecy. Personally, I'd try Viagra again but also just work on not getting too upset no matter what happens.
Anyway, good luck and just have fun.

I try to schedule sessions in the 30 to 45 mins range. Even though It costs more proportionately, but I don't end up paying for time I can't use. It the cost of growing older.

Getting old ain’t for sissy’s!

My Mom always says that line. Lol. Go visits the 60+ board here on TER for encouragement. I have lots of experience caring for older gents who have ED it takes patience & no expectations. You may want to try cock rings & purchase a good penis pump.

And I am still able to lay some pipe, under the right circumstances.  

First, perhaps give Cialis a try. For some reason, despite their similarities, I've had different results with one ED drug vs. another.  

Second, make sure you're following the instructions. You need to give yourself time for the pill to work (I find 90 to 120 minutes works best). Alcohol or heavy meals can also dampen the effectiveness of the pills.

Third, pay attention to your general fitness. ED drugs won't fix basic health problems that might be interfering with your love life. Good cardio workouts might help.  

Finally, explore your sexual fun beyond penetration. Nothing gets me more worked up than watching 2 women have sex. Perhaps there's a kink you haven't explored that might add some newfound zip to your experience.  

Good luck and remember it's about having fun, not about putting pressure on yourself. Some of my sessions end with a splash down and, by choice, some don't. But I always have fun.

I tried it once for the hell of it. Wow. What an experience.

Go to see a good Urologist and discuss options like Tri-mix or Quad-mix, both are local area injectables and have great results.

make your dick hard, . . . . . . .you need answers.  Lol

 
Viagra's effectiveness is often a matter of timing, where Cialis doesn't really matter because you take it daily, so theoretically, you are ready for action anytime a soft behind brushes against your junk in a crowded elevator.   I learned early on that, when it comes to Viagra, the maximum effective period starts about an hour after I take it, but I have friends tell me that they seem to be ready in 20-30 minutes, so a little experimentation is in order when you first start using it.  

 
The nuclear option is trimix, an injectable formulation obtained from a compounding pharmacy, where the strengths of the drug can be customized to fit your particular needs.  I use this for special occasions where I'm in a double with two ladies or an extended session of 2-3 hours.  It keeps most users rock-hard for at least an hour or two, and you do not go immediately flaccid after ejaculation, but stay hard enough for re-insertion, so it's great for MSOG-lovers without requiring a refractory period in between.  Time to take effect is usually about 5-10 minutes.  Trimix is also not affected by behaviors like eating a streak or drinking alcohol before use, like other ED meds are.  

If you suck on or chew viagra (it's quite bitter) also known as sublingual, it'll enter your bloodstream quicker. I've had it help in as little as 10 minutes. It'll also be a stronger dose than swallowing the pill because the stomach route is less effective.

I use the supplement male enhancement with viagra. You can cut a diamond it gets so stiff.

Just enjoy your time with the providers

You have nothing to worry about, you’re not the first or last we see with ED. It’s quite common in older men believe it or not. I personally try to make the most out of our experience, wether it be we keep teasing and playing with each other or keep trying with oral, I will try my best.

Look in the mirror, what do you see??? How'e your health. are you..??
Overweight? Do you eat fatty /shit food??  
Do you smoke, drink, sleep well? Do yo drink alot of water?
I would strongly consider some kinda of workout program, be the Adonis that you want to be. Let her see you as some 30 yo young buck...lol
If you're able to get hard for 10-15 minutes then I feel the problem might be between your ears. Maybe you're thinking too much. Maybe you're trying to justify the money you just spent and you feel to need to whack it out of the park with her....it's not a sprint.
One more thing, stay away for girls under 30, they could be bad for your ego...jus sayin
But what do I know, I'm just a dude playing doctor on some fuck board.

There are lots of short term options that other people have posted, but for overall physical health (and penis health!!) exercise, eat healthy, drink lots of water, get 8 hours of sleep a night. If you have high blood pressure this can also have an effect on the blood vessels of Mr. Winky. Alcohol and other drugs can also cause your buddy to not stand at attention. I have clients that are in their 60s and 70s that can still rise to the occasion, so don't think that just because you are getting older you are out of luck.  
Personal story: I just had a client email me that I have not seen in years, but I remember he was always lots of fun. He asked out of the blue if it bothered me that sometimes he could not get hard, and I did not even remember this being an issue as our times together were lots of fun and satisfying. There are LOTS of ways to have fun sexy time.  
You've got this!!

... so I can relate.  However, if you can find the right lady, you can work through it.  Only recently have I tried "help" (Blue Chew) and while it works for me, I had a wonderful experience with a lady who encouraged me NOT to use it with her.  We did our "dance" and I was able to perform exceptionally well with her.

I agree with the others about the psychological aspect of this as well.  Relax, don't focus on the performance and just enjoy the experience.