Maid kara Haha ni Narimashita - Vol. 1 Ch. 6

[MangaDex]

 

[wolfeng]

He doesn't care about marriage, and she won't accept to forget her past life love. They both marry out of convenience for Jill and voila, eventually they are actually in love with each other

 

[chronos5884]

Sid is quite sweet. He definitely gives off some nice vibes.

I do see the whole "older brother" vibe though. Oddly reliable.