I think J.R. idealized Sue Ellen when he first met her as Miss Texas. But Sue Ellen didn't want to be a trophy wife and so this relationship was dysfunctional from the start because there was only one woman J.R. really loved - in
Dallas' original run. Of course it's Miss Ellie! He had the respect of his father but Jock actually preferred Bobby to him and momma favoured Gary whom he detested for it. That was the family dynamic we know for sure. And that works as a decent psychological explanation why J.R. needed to succeed in business and didn't care enough for relationships with partners or within the family.
Yes J.R. told Sue Ellen that he loved her. He did it when it was convenient for him to reach his goal. Visitation rights or whatever concerning John Ross. For similar reasons J.R. would later profess his love to Cally. To get out of Haleyville or an asylum. J.R. gaslighted SueEllen into a second marriage. Or his tramps and escorts were not available for sex and he slowly started to respect Sue Ellen as a successful woman and he may have seen her then with different eyes and mindset. But I think J.R.'s love confessions to Sue Ellen were only true at the end (in TNT's
Dallas). When it was too late for both to live as happy elder couple he honestly meant it - at least then I believed it too.
As fascinating Sue Ellen and J.R. were as a couple to watch I know it wasn't love what made them
Dallas's main attraction: she hated him, he despised her most of the time, it was their battle to
build love they hadn't in the beginning. The Beaumonts offered a lot of story options to deal with that if they've kept Sue Ellen - it would have been a mirror situation to early Pam and Bobby. Only it's J.R. who realizes it's Sue Ellen he has to fight for. Not an old flame who's trying to steal the thunder with his adult son and not the young new wife who would be better off with that adult son. That was my wishful thinking when the Beaumonts appeared and I would have loved it when Vanessa had copied Sue Ellen's American style and tried psycho tricks to get her out of the picture. Sue Ellen's female nemeses were never long around but this one would have more sense than the tramps. Classic
Dallas lost the plot when they let Linda Gray go but thankfully TNT's
Dallas repaired that and gave them closure (while destroying poor Cliff Barnes, but that's another story).