This can be annoying sometimes. Others mentioned SSRIs, I have never taken them, but have often read about how they can cause this issue, and are sometimes prescribed for premature ejaculation.
A key factor is learning about your body and what gives you the most pleasure. When I was younger I often came too quickly, and as I worked through those issues, and became older and more experienced, now the pendulum has swung to the other side. The tighter a woman is, the easier it is for me to cum. Hopefully I can increase my girth to a point where all women feel ultra tight!
My main strategy is using positions that increase tightness. I don’t know what it is called, but the one where you start in missionary, and then put your legs so they are on the outside and squeezing her legs in. This definitely increases sensation more than any other position.
Feeling disconnected from your partner emotionally can also be an issue in long-term relationships. A feeling of detachment is certainly not conducive to orgasm. Remembering to get out of your head and connecting with her can often be effective in achieving orgasm.