Well if you have had multiple partners STDs need to be ruled out because some of them can cause problems with fertility. A doctor can do a blood test for this.
Sometimes too much sex or masturbation can make it difficult to maintain an erection, but besides that I'm out of ideas. I'm sorry, maybe someone else on here has some advice for you. The only thing I can think of is suggesting you talk with a doctor about erectile dysfunction.
Yes i have been sex with other girl before but their all not a virgin, their with some kids too.thus easy for me too have sex with them. but still , i know my pennies not enough strong.
I still dont have that kind of daring to talk about my problem with my girl friend.i know she is not a sex minded but i think she need a good sex from me..
The hymen, which is a piece of tissue inside the vaginal cavity, usually breaks very easily (sometimes too easily and it doesn't even wait until the first time a woman has sex). You should have no problem breaking this even if you find it difficult to stay erect.
Have you never had sex before? If this is the case you will likely find it's very different from masturbation and it may be easier for you to stay hard. It's also very natural to be nervous, but when it comes to sex your body will kind of take over. Just remain calm and take it slowly. Once you relax into it, it tends to be easier. Just keep in mind that the first time will be hard on your wife. Typically a woman's first time feels a little awkward, uncomfortable and many times can be very painful. Sometimes this is true for the first few times that that woman has sex, so be gentle. I'm sure she's just as nervous as you.
Do you feel comfortable talking to your girlfriend about this? Honestly if she really loves you this wont matter. Yes it might make things difficult if you find you can never get hard but there is so much more to marriage and love then sex. Let her know you worry about making her happy and satisfying her and I'm sure she will be appreciative and patient. Also, personally I have found that an open communication about sex make sex much more pleasurable for both parties. This conversation will probably have to wait until after marriage but knowing what feels good for her and helping guide her to know what feels good for you will make a big difference in your sex life.
Some men find it easier to keep an erection if they cut out or down on masturbation. So it might be helpful for you to try that. However, if in the end you find that your difficulty maintaining an erection is more than just nerves you might need to talk to a doctor. There are medical interventions and things that they can do to help you.