I need to know should i leave my man i been with off and on for 4 years ...i know he daten a older chick?

He call her kids his step kids..Im i just beein use up and playd he dont see me often every other week ...I all ways see his car at her house ..Should i just stop answern his calls for few days to show hem im not worried bout hem..WHAT SHOULD I DO""""""""""""""???????????????????