How much natural lubrication you produce is strongly influenced by the production of hormones and they are likely to change during and after pregnancy.
Pregnancy and childbirth, in particular, can wreak many changes on a woman's body, some temporary, some less temporary, and some permanent. Some lucky women do quickly regain their previous vaginal proportions; size, shape, and internal texture but for others, especially those who forego the recommended post-natal exercises, the birth, especially one where the baby is in the birth canal for a protracted period can wreak havoc with those things so that afterward it is like suddenly having a different vagina - a vagina that has a very different size, shape, and internal texture so that increased lubrication or even the same amount of lubrication can seem too much.
The owner of such a vagina is unlikely to notice these things as much as her partner but if he is a gentleman he will be unlikely to say anything even if asked...
It is likely before birth your vagina was like a sleek sports car but after birth, it is probably like a large and ponderous old family saloon car (by comparison). Both vehicles will get you where you want to go; they have to be driven differently...
Some exercises dedicated to developing and gaining conscious control of the abdominal muscles that support the vagina could help a lot.