Is it normal that my bf bites me & pinches me?

Ok so me & my bf have been together for 5 months,he has a 2yr old little brother who plays around with him by bitting each other,his mom also likes to do so,they play on the floor punching,bitting & tickleling each other,when I started going out with him,he would throw me in the grass and tickle me he also likes to take off my shoes & tickle me,which I found very fun & cute,until...he started bitting me specially my fingers,my lips & toungue,he started pinching me on my arms & stomach,he started punching me on my arms & stomach( not hard) so I gave in & started doing the same to him.so one night we were on the phone,he was telling me wat a nice & cute gf I was,he said"I remember with my ex gfs,they used to get all butthurt & tell me to stop whenever I played around with them"I don't wanna b like his ex gfs & dnt play around with him knowing he likes to do it. I guess he likes to play around like that? Is it normal? Help!