After some research, these are my conclusion:
From what I read, Paris is always magnificent during summer. But the downside are steep price hike for flight and accomodation because of high demand from tourist. Not to mention the crowded situation at almost every major attraction. Climate can be quite hot and humid which is nothing new for visitors from Malaysia. One positive point for us at that time, summer are like eleven months ahead and we will have more time to plan and prepare if decided to visit during this season.
Spring in Paris is from March until June. March is the end of winter and the climate is still cold. The temperature is more acceptable for me in the months of April and May (about 10C to 20C). However, some travellers mentioned about the rainy season in April. For both of us, enjoying the beautiful 'Jardin' is a priority and we can't do that if its rainy. Daytime in May is longer than April, so we will have more time for sight seeing.
After satisfied myself with the information, I became excited about Paris and like 70% positive to actually making this trip. So when should we go? Summer is great but it's too long to wait. Looks like we shall go in May.
What is the lesson learnt from here?
Beware if your partner randomly pop any travel idea.
Chance are you'll end up going there!