The gemara means you should refrain from the PLEASURE of marital relations as a way of SHARING THE PAIN of the community at large. The beraisa states that the mitzva of having children overrides this concern.
It is clear from Rashi, as well as the context of the gemara, that the OP misunderstood this gemara. (It is also clear from tosafos, who limits this restriction to middas chassidus, that this is not a practical concern of having too many mouths to feed.)
I have NEVER heard this gemara construed to have anything to do with too many mouths to feed.
I never post on this site, but I am afraid the gemara is being misunderstood.