Connell doesn’t want to merge his two lives because he’s afraid of what might happen to both sides of his current existence. On the one hand, his life as a popular boy in secondary school might be ruined if people find out that he’s involved with Marianne. On the other hand, his relationship with Marianne
also might be ruined if his friends make fun of them for secretly seeing each other. Not wanting to lose both, he fantasizes about somehow keeping the disparate parts of his life from merging, but in order to keep them from colliding, it’s obvious that he’ll have to make a decision at some point—in fact, he already
has made a decision by deciding to go to Trinity with Marianne, though he doesn’t necessarily see it that way yet.