Weed may be the culprit or contributory.
The absence of orgasm is called Anorgasmia. The causes are usually divided as follows;
2) caused by certain medications
3) decreased penile sensation owing to impaired pudendal nerve function. Most commonly, this occurs in diabetics with peripheral neuropathy. Men who experience anorgasmia in association with decreased penile sensation should undergo vibratory testing of the penis and further neurologic evaluation as indicated.
Following is the protocol for the work-up;
1) Stimulation of the penis with a vibrator or other stimulatory device to determine any underlying physical (neurological) problem.
2) A neurological examination; to determine other nerve problems.
1) Sex therapy sessions; reduce performance pressure and focus on pleasure. About 20 sessions may be needed for the optimal outcome.
3) Withdrawal of the medication; if one is considered the cause. Weed may be stopped.
4) Avoidance of stress, anxiety, and other factors. Enjoying the sex, changing position for best glans stimulation and partner's effort also play an integral component in the positive results.
You should consult a urologist for an initial evaluation.
Please feel free for your follow-up questions.