Hi cjbo32, Dale
I can't think of any direct equivalent in Irish either.
You might say something like seasfaidh mé leat i gcónaí for I will always back you up, I will always stand up for you, etc.
Seas means stand, so literally, this means I will always stand with you.
For always, I'd use i gcónaí.
As Dale mentions riamh can also mean always or ever, but I've only ever heard riamh used when referring to the past, or in the sense of always from the beginning. For example, bhí sé riamh cantalach, he was always cranky, or sheas mé riamh leat, I've always (from the beginning) stood with you, I've always backed you up, etc.
Using both riamh and i gcónaí...
Sheas mé riamh leat agus seasfad i gcónaí! I've always stood with you up and I always will!
(seasfad = seasfaidh mé)
Other possibilities that might work are:
Beidh mise mar thaca leat i gcónaí, I'll always back you up, I'll always support you
Taca means support or prop, so literally, I will always be as a prop or a support to you.
Beidh mé ag coinneáil súil i gcónaí ort, I'll always be looking out for you