I'd be more worried about the gourami than your betta. From what I've heard, they're the closest cousin to the betta and they'll be likely to fight it out.
According to http://forums.gardenweb.com/forums/l...340429892.html
"Depends on the gourami. Some gouramis can be fiercely territorial. Stay away from Kissing fish (which are gouramis), blue gouramis, gold gouramis and platinums. Moonlights and pearls are fairly peaceful. So are honey gouramis and sunset gouramis (both are dwarf gouramis)."
"In general gouramis and bettas dont mix as they are both anabantids with bad attitudes..."