Hi,
Do you have this problem right from the start of the marriage? Or even before? Or did it start a few days/weeks after your sex life within wedlock started?
It is likely that your efforts to avoid
pregnancy is having an inhibitory effect on your mind. It is subconsciously preventing your sexual excitement to reach levels required to trigger ejaculation.
This can be overcome by replacing the condom method of
contraception to other methods such as
contraceptive pills, which are highly dependable. Try this first for a few weeks.
A second possibility is that you may not be receiving adequate stimulation (again to the peak level required for triggering orgasm) from peno-vaginal sex, compared to what you are getting from
masturbation. If this were the case, then experiment with different foreplay techniques, coital positions etc. Encourage your partner to do foreplay to you and physically stimulate you during intercourse. That would help boost your sexual excitement to higher levels and trigger orgasms.
Many other factors such as use of alcohol, prescription drugs etc could also play a role in such problem... if the first 2 methods of management don't yield results, please consult personally a sex therapist near you.
Best wishes