Would you end your relationship if this happened to you?

I would ask him what his intention was, and if he deletes and never contacts again I would continue if not I'll move on. 

It's called cheating. It's time to move on.

If you are not yet exclusive, why would this be a problem? On the other hand, if you are exclusive, yes, I'd be done with him.

You're not giving a lot of detail here. There is always 2 sides of a story. How long have you been dating? Is it official? How do you know about the contact with the Tinder matches? 

My guess is, you are feeling angry (which is completely understandable) and that you are trying to back up or validate your anger online. If you love him.. and note that you're not mentioning any love or hurt in your question, then my guess is that you would have phrased it a bit differently. 

I'm not suggesting that keeping contact with ex's are indeed okay. But I'm suggesting you rething the level of committment you're trying to achieve here.Are you jealous for selfish reasons or your own ego? Or do you love him and want to spend forever with this person?

I would not like it at all if my bf was keeping up with his tinder account at the same time as dating me. That would be a deal breaker and I don't think any woman with good self esteem would allow it. Tell him how you feel and if he wont commit fully to you, I'd move on and quickly too!

I'd struggle with that because I wouldn't feel they were committed to me.  Instead, it seems like I'm in competition with his other Tinder matches.  That doesn't work for me but that's me. 

Depends. Do you trust him? Has he given you any reason to not trust him?

I dated on POF.com for about 2 years. Until I met my current wife, I met a lot of great ladies. To this day, I am still friends with about 4 of them, and hang out with 1 of them on a regular basis. Of the 4, I had sex with 2 of them.

My wife knows me. She trusts me. And she's mature enough to know there is nothing wrong with a man having female friends, just like there is nothing wrong with a lady having male friends.

Yes, and I have had to. Keeping in touch with them means that he's probably still considering them and I think it's too sneaky. So I would probably end it. As I said, I have before.

If I was in a monogamous relationship, yes