These lines remind us of the story of Adam and Eve. In Genesis, the first book of the Bible, God creates Eve from Adam's rib, and they are thus described as "one flesh" in Chapter 2, Verse 24. Could it be that our speaker thinks that her relationship with her husband is like Adam and Eve's, a near-perfect marriage worthy of paradise?
Thy love is such I can no way repay, The heavens reward thee manifold I pray (9-10)
The speaker's husband's love is a very powerful, spiritual love. It is so other-worldly that only something supernatural – the "heavens," or perhaps God – can "repay" him. Our speaker could be saying that her husband loves her so much that he's sure to get a ticket straight to heaven.
Then while we live, in love lets so persevere, That when we live no more, we may live ever (11-12)
Reaching heaven – living forever ("live ever") – is all about love. Yet, it's not just about loving one's husband. All the speaker says is "in love let's so persevere." She could be saying any number of things. She could mean that she and her husband have to persevere in love, which is sometimes tough. Or she could be saying that as long as they stay in love, they can persevere through anything. What do you think she really means?