TroubledMay your sails catch wind
First thing: This is a very sweet poem. Second thing: This is not a great poem. Yet.
The first four lines are lovely. It reminds me of traditional blessings, especially since it's nature-based. It has some language issues (catalogued later), but in mood and execution it's quite nice. The last two lines don't quite seem to fit with this sentimental opening, and they're not really explained - what lie is involved, and if it's not what's tying him, why is it even mentioned? That final line feels like it was just thrown in there because "tie" rhymes with "lie." And that's never a good reason.
It took me a few reads to understand this. The only thing tying him to...possibly the sea, or possibly home...(I'll guess home) the only thing tying him to home is your heart? That's understandable. That makes a lot of sense. So why are the lines about tying and your heart in different stanzas? This couplet has a nice turn of phrase to it, but it feels empty since it's so isolated and we haven't really 'met' the narrator. I'd suggest re-evaluating the stanza break, but that "made from a tie" line throws that off too.
Now we get to know you a little. This is the only stanza that I connect with emotionally. The narrator's feeling of weakness, the feeling that this man has saved you, is very powerful. But again, there's so little actually happening. Two options for expansion: If this is a love poem, give him more to go on about the things you've done for each other and the feelings involved. If this is an art piece, make the narrator a more fictional version of you who feels even weaker and more helpless without him. Make it bigger, because this subject is one that really lends itself well to being BIG. This could be really powerful if there was more to go on.
"my love for you is double"? Seriously? I don't...I can't. This is simultaneously so saccharine it makes me wince, and so silly it reminds me of Team Rocket. Is that what you were going for? If so, scrap the entire rest of the poem and start over to keep this mood. It's so incongruous with the lovely blessing of the first stanza and the confession of need in the third. If you keep the rest, this just has to go.
Nitpicky issues (feel free to skip, although they may help):
In the third line, perhaps start with "may" again for consistency? That one's your call.
"As you ride the seas" not sea's
"my frail troubled heart" not trouble
Okay. So I tore this apart and I'm sorry about that. But there are some strong emotions in here, and those opening lines still make me smile. I'm being harsh because I think this poem could grow into something wonderful. All that said, your boyfriend is a lucky man, and I'm sure he will love what's already laid bare on the page.