Thanks for your query.Based on the facts that you have posted it appears that your partner has problem of erectile dysfunction
and anejaculation .
He has undergone circumcision
with the hope that it will improve his ejaculation .
I would like to state that circumcision does not help improving erectile dysfunction ,but helps in penetrating vagina during sex.
As regards his problem of not getting ejaculation try to spend more time in foreplay and delay intercourse so as to get sufficient stimulation of glans
.If problem persists consult qualified sexologist
for clinical evaluation and further treatment.