I've always been rather puzzled by Clive in this section of the novel, and I'm not sure I understand him any better than I did in the past but this time I was struck by how unhappy he seems to be. It feels like he's reached the breaking point. Whatever pleasure doing the conventional thing of studying for the bar gave him, clearly having reached his goal he's dissatisfied and doesn't find it fulfilling. The influenza and the rest involved in the convalescence probably gave him lots of opportunities to reflect on his circumstances, and when Maurice had it too, the routine of having him in his life got disrupted, and he realised it didn't give him much beyond the routine.

After all that, I'm not surprised that their relationship is falling apart.

I suppose the bed episode is Clive's one last attempt to see if he can get anything out of the relationship, and the answer seems to be no.

I think Maurice tries to cling to itthe relationship because he cannot imagine his life without it and Clive in his life.