This is simple, your "man" has lost interest. If he were totally in to you, and wanted to be with you, he wouldn't have made contact with the ex, and would have told her off already, but he hasn't. The whole infidelity factor should be a big enough clue to you that it's time to go. If he's cheated on you and your are still staying around, you should stop thinking and planning about "getting him back" and more about getting rid of him. Once he's lost interest and is talking to other women, it won't stop...

I don't understand how he's even "your man" if he's having a relationship (thru Match.com) with another woman..

***If you don't know where you are going, any road will take you there. Lewis Carroll (1832-1898)***..

He is not your man (by his actions)  She can't take him (he will go willingly).  He is not some possesion that either one of you can control.  He has made a choice accept that and move on..

Leave the man alone, work on yourself so that you can understand that you can't make someone do something that they don't want to do.  Even if you could, would you actually want someone you had to force to be with you?  If so, you need to work on that issue also...

I am a believer that you always fight for what you want.  but you also have to know when it's over.  you fight and let him know you want it....but if he does not say that he wants you.  move on and leave him be.  regardless of his excuses or reasons. ..

If talking things out with him and giving things another chance didnt work .. then I'd say that you need to part ways.  If you have to convince a guy to have a relationship (thru Match.com) with you .. then I feel that the relationship (thru Match.com) .. as you described it (infidelity, communication issues, nagging interrogation) is not one that is enjoyable to either one of you.  think of the climate the two of you have created .. no wonder the other woman is looking better right now.  Sure .. maybe he'll cave into your pressure for a little bit .. and then move on anyway. .

The concept of "fighting for your man/woman" really only works for men.   For some reason when women do it .. we just look desperate instead of in-love.  .

The only smart strategy here is to let him loose .. plan a life without him right now ..  let him see that you are together without him an attractive quality to men.   And let him come back to you.  It needs to be HIS decision .. in order for him to 1) have no regrets about letting other women go, 2) for  him to be 100% sure about you - if you pressure him .. then he'll always wonder about the other woman...

Why would you want this guy? Why would you put up with him contacting his exgirlfriend?  And if a guy said to me I'm a nag???? Well, see ya later honey... I'm walking..

By the way... he's not your's... nobody owns nobody...