Need advice if i should introduced solid to my 4 and half months old son?

my son have been so unsettle most of the time and he have infrequent poo( around 2-3times a week) and im breastfeeding, i don't think im supply is getting low however he is always have been very fussy and refused to latch in the mornings..he is still gaining weight thou..last month was around 100g per week..my husband seems to think solid food like cereal is all he might need. he does seem to have all the readiness sign, im told its Better to introduced solid at around 6months, im confused if i should try to give him solids or not...HELP