Jesus never had a mother-in-law of his own, yet he still had to deal with one...Peter's (Simon's).
Mark 1:29-31 (NIV):
As soon as they left the synagogue, they went with James and John to the home of Simon and Andrew. Simon’s mother-in-law was in bed with a fever, and they immediately told Jesus about her. So he went to her, took her hand and helped her up. The fever left her and she began to wait on them.
From my journal, November 17, 2000:
The first response of Peter's mother-in-law when Jesus healed her: service. She fixed dinner for them. In the same way, may I daily renew my sense of wonder at the love God expresses to me, and live out of a grateful heart.
Truth is...we don't do good things so Jesus will love us, but out of gratitude because He loves us.