The quote inJESUS posted is pretty much accurate. Birth control is in general allowed so long as it isn’t permanent, and is agreed upon between the spouses. Permanent measures like you mentioned are allowed if the woman’s health is in jeopardy, as it seemed to be in that case.
Allah in fact does use the terms “I” and “Me” and “My” in the Qur’an, just like He uses the terms “He” and “Him” and “His.” But never does Allah use the term “They.”
We is a dignified or majestic plural which substitutes for the singular in some cases without implying any kind of duplicity. If you want to read what the Qur’an says about the Trinity, I’d be happy to supply you the verse.
But you should know that sometimes Allah says “We” and sometimes He says “I.”
It is the pronoun of choice in one of my favorite verses, 2:186
And when My servants ask you, [O Muhammad], concerning Me - indeed I am near. I respond to the invocation of the supplicant when he calls upon Me. So let them respond to Me [by obedience] and believe in Me that they may be [rightly] guided.