Non-LC member dating an LC member--help!

It's rather ironic that the LC claim to believe that denominations are a division of the body of Christ whenever they themselves are being divisive by only meeting with "LC" groups. When I tried to mention this to the LC man (who I mentioned above) as well as to other LC "members", they would all argue that they are not divisive but welcome any one into their meetings. It was always an endless, argumentative cycle.