Am I wrong for feeling like this?

Me and my boyfriend have been together for almost 5 months now. He's been working for his ex's parents for almost 2years now. He hasn't quit because he gets paid really good and no where in ourn small town is hiring. They wouldn't pay as good anyways. So I haven't expected him to quit. He has a truck payment answer bills that have to be made.. Well, he works on their lawn crew, and he's had to go to their house here in our town to mow their yard and stuff twice. I was pissed about it.. Now his ex's mom has bought several new houses that she is going to rent out but needs cleaned up and re-done first. So she has asked the lawn crew to do it. Which means all the time communicating with his ex's parents.. They always bring up his ex too. Which pisses me off... Bad. Well today, his boss, her mom, asked Jim to drive to the town she now lives in and get a bunch of stuff for one of the houses. He rode back to our town with his ex's mom and younger sister.. I'm quite livid about it. It makes me soo mad... Am I wrong for being so mad about it?? Please help.. Its driving me insane and causing problems.. I need someone else's opinion...