Please discuss this with your doctor, or hers. It really sounds like you need a general education about what happens in sex and the difference between sperm, semen, and a woman's fluids, and that the door is not closed to sperm entering a woman's uterus after her orgasm. If you feel she has an unusually large vagina and are not having sensation when you insert your penis, ask her to go to her doctor for a gynecological exam to make sure she is not unusual in any way, and if she is not, you go talk to her doctor about the problem you are experiencing. Women's doctors are often better than a man's own doctor at helping explain human reproduction and the physical parts of sex, and it would help for you to be asking from someone who can explain clearly to you.
Oh, I see you already asked this and had answers. Please do not start a new thread for the same questions. As anniebrooke stated, sperm always comes out of any women. But what really happens is that it is the fluid the sperm is in while the sperm head north toward an egg. The fluid part then will come out. She can try putting a pillow under her. This elevates the hips and helps hold all the fluid in longer if this is what you are concerned about. It takes the average couple a minimum of a year to become pregnant, so keep that in mind.
So, I'm trying to follow what you are saying. Your penis releases in that it is not staying in her? She is not tight around you? Or do you ejaculate quickly? Not exactly sure what you are asking but will try to help if I can.