Imagine a woman you've known all your life has just gotten married. You were at the wedding, and you could tell she was really happy. Well, now it's a few days later, and she's still glowing. You swear that you've never seen somebody so happy. She won't stop talking about how great her husband is, about how amazing their relationship is, about what an incredible chemistry they have, and on and on and on.
Now pretend it's ten years later. You're in town on business and you pay your friend a visit, and guess what? She's still as happy as the day she got married! It is at this point that you realize she has experienced true love, a fact you confirm when your friend shows you a poem she's recently written called "To My Dear and Loving Husband." You knew she was in love, but so in love that she's started writing poetry? That's the real deal.
And that's our speaker in a nutshell. All you need to know about her is that she loves her husband, a lot. In fact, not only is that all we need to know, based on this poem, it's all we can know.
Of course we might make the leap to assuming that Bradstreet is the speaker (although it's never safe to assume the poet is the speaker in her own poem, unless she explicitly says so). If you think this is a plausible conclusion to draw, check out this biography, which might provide some insight about the effects of Bradstreet's life on her poetry.