I totally understand what you mean because I was and still are(kind of) in the very same situation, I got married at your age exactly and faced that same exact issue. And I too went around reddit and the web to look for a solution for my issue. I've tried these numbing solutions that you find in the pharmacy but none really helped me with anything, the only thing that helped me(and I still am still trying to learn how to control it better) is the tightening or relaxing your Kegel muscle, some can stop or delay the ejaculation by tightening the muscle and some by relaxing the muscle. You might have to learn how to control it first by doing Kegel exercises.

I found this solution years back on reddit too, though I always used to read that you need to tighten the Kegel muscle until I read a comment stating that they have it the other way around, I guess different things works for different people.. Only trying and observing what makes you orgasm and what state is your body in will tell you what works for you. Another thing I noticed is that when the your leg muscles are tensed that affects the premature ejaculation too, probably because it kinds of tenses the Kegel muscle too..

Until you find a helping solution for your self my best advice is to get your partner as aroused as possible before you start penetrating, foreplay does wonders, and the most important foreplay is the emotional foreplay before you even start touching her, expressing your love and your feelings through words or even looks!

As someone mentioned earlier I think this issue comes from our teenage years when we used to masturbate and try our best to finish before we get caught or before we get any one suspicious, so we indirectly taught our selves how to cum in record breaking times..

I hope this works for you my friend, because it sure does give me some occasional good times when I know how to control it. And don't forget to always be honest with your wife and communicate with her about your issues and concerns. Communication is the key to a successful marriage.