Bh made it to day 64!! However keep having desires. to try and find a way to reach porn. I’m worried I’m not going to make it ... and Yetzer harah is telling me “you’re bound to fail eventually even after 90 days , do why try now?” Anyone have any ideas/chizuk? 

I would recommend staying focused on the present moment. Listening to the Yetzer HaRa anticipating that you will eventually fail sometime in the future is not going to do you any good. Right now, you are not failing. Right now, you are on day 64.

Also, don't let "perfect" be the enemy of really really good. I, of course, hope that you don't fail after 90 days and I wish you great hatzlacha in being porn/masturbation free forever, but even if you do fail after 90 days, you still had 90 days! Why does failing sometime later make the trying and succeeding now not significant?

Just some thoughts...

I love this answer. Reminds me of Rav Yisocher Frank's speach at the siyum hashas. Perfection is the enemy of good. 

Regarding the 90 question, at the same time that you have to keep pushing, make sure that you take it one day at a time. Truthfully, and if some would argue please do, for many the 90 day chart is great... All you have to do is be abstinent. For myself though, I just like thinking that every day is day one on the streak. You know that feeling, like I'm gonna do it this time, let's try something new... Why do we wait until after a fall to do that. If your feeling strong urges, reset and refresh your situation. 

Another big point What has been working for you so far, what is making you stressed, what can you change? The goal is long term success, and since life is ever changing, your plan for sobriety either always has to change with it (which is exhausting) or you need to have some internal change. When you change internally how you think about porn, how you respond to pain, and anger and urges, what happens when your triggered... It's really helpful to keep track of where your holding so you can 1 track success and where you've done well or not as well and 2 make sure that no matter what hits you, that's fine, you'll always be sane and at a place of complacency... That's the goal... I think. To not be swayed by what's going on, and have an internal constant peace. 

If if this is gibberish to you, maybe just start tracking the way you react to certain scenarios, and think of what you can do to change that for real, not only on the outside, but on the inside as well to have a real true paradigm shift about how you approach your experience of the world.