Sonnet 87 describes the termination of a relationship. Interestingly, much of the verbiage refers to legal terms (charter, bonds, hold, grant) which suggests that the contract of the relationship has ended. No where is the word "love" mentioned; the relationship was, or has become devoid of love.
The speaker in the sonnet conveys the sense that he was not worthy of the relationship, and that his beloved had come to realize "true value" ("thou knowest thy estimate") but this could be an ironic commentary on the vanity of the person the speaker addresses -- the speaker was actually "too good" for his beloved.
"My patent back again is swerving" refers to legal instances where patents, or licenses had reverted back to the Queen (see link for more descriptive details.) In this case, the speaker asserts that (again, perhaps ironically) since you were too good for me, what claim (patent) I had upon you is concluded, and it now reverts back to you.
The couplet implies the speaker had been dreaming about the validity of his feelings towards his beloved, but once waking, realized there was nothing to it (no such matter.)
The interesting use of "flatter" again suggests the Ironic Reversal - the speaker has metaphorically been asleep, and in being in such a state, was subject to the flattery, or privileges of royalty by the liasion with his beloved, but once he awoke he realized there was no such situation.
The last two lines, then suggest that the whole poem is flattery towards the former beloved -- rather than directly accusing the beloved, the speaker pretends that he was the cause of the relationship's dissolution, when in fact, it was the other way around.