can you help me with title of drama/song?

i'm trying hard to find out the song title of this drama.i watched it long ago n didn't remember the title n actors' names.i know the actors but can't find their faces in the actor database in this site.the story being this man(actor has very small eyes n wears glasses) aged in maybe 30-40s who has a very protective mother(a well-known old actress who also plays a teacher to kids of 3 couples in another drama).the son became sort of a weirdo n he later married a woman who is a good wife but the marriage has many problems n unhappiness.she became pregnant but the man initially didn't believe the baby is his.......
the theme song is my all-time fav.i'm not sure if i remembered correctly that the band who sang the song is Tube n the title may contain words 'mo ichido'.this song was covered in chinese by nicky wu.
does anyone who also knows if this japanese song is available in any
thanx.

Hmm... even with all that, it still seems pretty vague. When you mean you watched it a long time ago... 20 years again? 5 years ago? How long?
You mentioned "Tube" and I think they're a recent group.

The drama you searching must be "ずっとあなたが好きだった(Zutto anata ga suki datta)".
Zutto anata ga suki datta ずっとあなたが好きだった

And the name of the theme song is "涙のKISS(namida no kiss)", not Tube but Southern All Stars.
"namida no kiss mo~ ichido~~ dareyori mo a~i shiteru u~~ "

re

many thanx!
i think the drama you said is the one i'm looking for.the title 'i've always loved you' is familier n has actors nogiwa yoko n sano shiro who played mother n son in it.
wonder if you know if there is any compilation albums of theme songs from japanese dramas that has the song 'namida no kiss'.i also like others like 'true love'(fujii fumiya) from drama 'asunaro hakusho'.
i'd wanted to buy a recent album of hits from various j-pop artistes(namie amuro,V6 etc).but read from a review that the album did not contain the WHOLE but only part of each song,so i rejected.