Since you identify yourself as a young parent and tithe 10% of your income, I’ll go out on a limb and say you’re LDS. It’s not uncommon for young LDS families to struggle financially. I would say that’s true for most twenty-something families with children and one income.
If you are set on one income and remaining in San Diego, I would recommend ratcheting down the budget even further to increase your savings and future homebuying power.
Otherwise, if you are LDS, I would relocate to Utah.