I have tried to help my friend to make his wife pregnant. Once we got used to having fun and tried to limited within the bedroom and don't talk about it outside the bedroom, it seems ok.

see  forum.timway.com/f/thread-168146-1-1.html

When you see other man having sex, you may try to have it again. It will give your wife 2 or even 3 shots. But the person who helps to do 3P, should be under your control or like a helper. Otherwise, you will feel bad. For example, he can kiss your wife. I did not do this in front of her husband. I think no husband can stand watching another man wet kiss his wife.

When the man fucking, your wife still kissing you and hold your body, rather than the other man's body.  I tried to do this so that my friend won't feel bad.

Eat more seafood, e.g. osyter, mussels, lobster. It helps. They said fisherman have more children than farmers.