Most Helpful Guy
So let's summarize this. You say you broke up with him because he wouldn't 'define the relationship'. To me that sounds like he wasn't giving you the level of commitment that you wanted. Which would then make me think that he wasn't as interested in you as you would like. You chose to breakup with him, respect that choice and forget about it.
He's on Tinder looking for other women, end of story. There's no way you can know if he has feelings. Obviously when you were together his feelings weren't enough, otherwise you wouldn't have ended it. So how can you know if he has feelings now? If you match with him? A lot of guys swipe right on every girl regardless of whether or not they like them. If he wanted you, he'd find a way to contact you. He's not on Tinder specifically for you, just forget about it.
Most Helpful Girl
Id say leave it to see if they do something first