The man starts off by saying that he ever since he got a girlfriend, he has been spending at least RM100 on meals with his girlfriend. In one day, there are 3 meals, so the daily amount that he needs to spend is about RM300.
In about 2 weeks, which is 14 days, he needs to spend RM 4200 JUST to feed his girlfriend!
As his salary is just RM 4200, it means that he can sustain her only for 2 weeks and because of that, she is trying to break up with him.
At the end of the post, he wonders if only people who earn RM10k per month are eligible to date.