Hi, and thanks for your medical question on eHealth forum!
Your problem could be because of dry vagina, which got injured during sex. This observation is based on the fact that you feel a need for lubrication, whereas the foreplay is usually sufficient to amply lubricate the vagina. There are many problems that cause vaginal dryness such as hypothyroidism, Sjogrenâs syndrome, vaginitis or inflammation of vagina, dermatitis of skin around vagina, condom allergy, or allergy to soaps and lotions. Low estrogen is another cause.
Sometimes the foreplay is not adequate for the female to be aroused as the arousal time of the two partners is different. At times no cause is found and water based lubricants are the only solution. Also, you need to rule out fungal infection and STD. Since a confirmed diagnosis cannot be given on net please consult your gynecologist once. Hope this helps. Take care!