Welsh-speaking Mumsnetters - I need your help!

[ParadeMeeting]

Hello! My DP is Welsh and I'm not Welsh but am learning Welsh (beginner-level!).

I'd like to get him a present engraved with the following Welsh sentence on it:

Mae fy nghalon yn berchen i ti.

I just want to check that the spelling and grammar is right, and that it makes sense!
Diolch!

Bump:))

Literal translation is my heart owns you

I would go for something simpler.

Ti a fi am byth (You and me forever)
Cariad (love)
Yn fy nghalon am byth (In my heart forever)
Ti'n werth y byd (Your worth the world)

Thank you so much you two!
So does the concept of "having someone's heart" not translate in Welsh?
@oldevilowl thanks so much for your suggestions!
DP has a life limiting illness, so things with 'forever' upset him so just to tweak 'yn fy nghalon am byth', how would I say "you are in my heart" - would it be:
Rwyt t'in fy nghalon

Or any other heart related sentiments?

What about...
Chdi ydi’r peth gorau i ddigwydd i mi

• you're the best thing to ever happen to me

Maybe 'Yn fy nghalon o hyd' might be better? Always in my heart ❤️

Thank you