My partner ejaculated on my stomach, some slid down my thigh; however i wiped it away before it reached my vagina. should i be worried about pregnancy?

Not very, but...: Viable sperm can be found in the "pre-ejaculate" as well as in the main load of semen. Although the numbers of sperm are much smaller, there is still a slight chance of pregnancy. Timing also plays a significant role. Where in your cycle were you. The chance of pregnancy is greatest in the few days before til few days after ovulation.

Not really: Miracles can happen but unless you are having unprotected sexual intercourse and your partner ejaculates inside, this scenario does not seem likely.