Hi,
Welcome to HCM.
It is nice to know that you are trying for a baby. Yellowish
vaginal discharge is due to yeast infection. Get your girlfriend examined clinically and get treated. Neglect will only result in foul smelling discharge and more complications.
She should get vaginal swab tests done, blood tests to rule out
STD. Watery light brown sperms can result due to infection. You should also get clinically examined. Treatment will depend upon the severity of the disease detected.
Both of you should take care of your hygiene and drink plenty of water. You should have your sperm analysis done. Watery sperms can result due to
low sperm count. Any abnormality detected will get treated.
Take well balanced nutritious, high protein diet, include fruits, nuts, berries, veggies, dairy products, meat in your regular diet. Take proper therapy under the treating doctor, therapy may go for 3-6 months, have patience. Take care.