There is alot of change from being single to being in a relationship. The way you think or do things changes, you start thinking about your partner, and spending more time with them, rather than your friends or even evening in on your own. Your life becomes more happier, you feel like anew person and everything is all jolly.
The only downside I would see is the arguments that happen or the question of taking things further, sometimes theres one who isnt ready for it.

Alot of people say that its better being single, even i have mentioned in a post about the advantage of being single, but its always good to have a partner especially they become your life partner.

we live in wats known as "WORLD" which is neither heaven nor hell. here theres nothing thats entirely good or bad. all good things always have atleast one demerit. thats d case even here.

its always cheerful n joyous 2 b in a relation, but if it comes 2 arguments n quarrels, d point is we ought 2 b able 2 judge n decide d perfect mate for ourselves before falling into a relationship. unless n until we know d person in full n also we like him, we should nevr think of any relation with him.

test d person u like, observe him n then go ahead for a relation. this eliminates all d disputes. Infact some ocassional arguments may arise as one among d couple may b busy/irritated at some time, or disputes in likes/dislikes, or due 2 external comments, etc. But these should not b taken seriousely. After all some misunderstandings are always required for a better understandng!