他為什麼約我食飯?

there are 2 possibilites. 1 good, 1 bad.
1. He misses you, after u guys broke up for 3 mths and business trip in singapore for 2 mths, total of 5 mths. He became lonely. When a person became lonely, he would think about all the good things in the past. For example, having a good girlfriend.

2. He just need someone to eat with, thats all.

In this case, you said 為什麼約我食飯呢? 我去吾去好? 我好想去呀!! , i dont really know you true feeling of it and what is the status right now between you too, For example, deep down in your heart are you asking this .....Is it because he misses you and wanna get back together, so ask u to dinner?

But by the looking of your question, are you still friend with him even tho u guys broke up? if u guys are, having a dinner is not a big problem. Go ahead.

You should ask yourself a question - why you broke up with him?
Initiated by you? or him? or both.

If you - It's your call. He may not give up yet.
If he - He may regret for his choice. Just say No if you don't love. Otherwise, you'll be his playmate only.
If both - Just say NO and be fair to your true love. It doesn't work.

首先你要記住一件事, 分左手都可以做朋友嘅!
相信你都識左你男朋友一段時間,唔理你地係點解要分手, 當初係相愛過先會拍拖..係咪?你都會關心一個識左好耐嘅人,何妨佢重曾經係你男友喎..見下面食餐飯...好平常姐!
見下佢, 俾佢知道你里幾個月都生活得ok都好呀...or你都掛住佢, 係咪?唔好自己呃自己,掛住佢咪見佢囉, 你平常心就得架啦...
呀...著靚啲, 醒啲...要俾佢知道you are charm & pretty呀！
我經常都要去新加坡分公司開會, 要唔要我帶啲野送俾佢呀!...有須要出聲啦..支持你呀!

佢約你食飯可能有好多原因..
唔一定係有d咩企圖既
可能係佢之後會去新加坡一段時間
所以想見下你同你講聲再見姐

我就覺得你不妨同佢去食飯
再見亦是朋友丫麻
其實有咩野面對面傾會好d
可能佢有野搵你幫手都唔定呢!!

掛住你囉。但如果已分手一定係唔啱大家，唔好去啦。無結果架。waste time la. 快d forget him la. 單身有希望！

分了手便不要去. 男人十居其九只是想短聚(九龍塘).妳又對佢未死心, 食硬妳.