I have had unprotected sex with my husband for 5 years and haven't conceived. He has two previous kids. Clomid (clomiphene) or vitex?

Get checked out. Clomid (clomiphene) is a better choice, there's no evidence vitex helps. 5 years is a long time trying to conceive at any age. Do you have regular periods? If regular you're ovulating (releasing an egg) every month. You should see a fertility specialist (reproductive endocrinology and infertility or rei) to check for blocked tubes, low egg supply, problems with your uterus or sperm problems (even with 2 kids).