As this scene opens we are presented with a side that obviously has clear divisions that are opening up between them and threatening to tear the conspirators apart. Firstly, Cassius is angry with Brutus because of how he punished Lucius Pella for accepting bribes, but then Brutus is also angry with Cassius because, according to him, Cassius did not give Brutus money when he asked for it to pay for more legions. The only thing that (temporarily) pacifies the two of them is when Cassius threatens to commit suicide to prove his love and loyalty of Brutus. Note what Cassius says:
For Cassius is aweary of the world:
Hated by one he loves; braved by his brother;
Checked like a bondman; all his faults observed,
Set in a notebook, learned and conned by rote
To cast into my teeth. O, I could weep
My spirit from mine eyes!
Of course, we don't know whether Cassius is being sincere here or whether this is another deliberately calculated move to manipulate Brutus, as he has already done so successfully. What is clear however is that although the situation is temporarily pacified, we as an audience question how long it will be until these issues flare up again.