Trying too hard to maintain an erection resulting a premature ejaculation

Iam a 168cm 100kg (obese).

When i try to erect myself, the blood stimulates so much and i start 'squeeze' my thigh to get an erection.

However the arousal i needed causes me to prematurely cum.

So when i thrust to my partner and then i felt like the dick becoming weaker, i try to maintain the erection but i cum fast everything it is hard and thrusting again.

Plus i get all sensitivity from the arousal too fast resulting a cum.

How do i fix this?

Is it due to my bad weight health giving me harder to control my erection arousal?