As the husband of a daughter and your mother in-law want a love-making with you.
Are you going to do it...or tell your wife about it.
And she supported your family at the credit crunch time...so she now ask for a favour from you, are you going to give it to her or what?
None of the options above is right for a wise man and phyuking Ur mother in-law to show appreciation for what she has done is an abomination.
Pls, dont do it and never tell Ur wife cos she will never believe her mother could come so low, to demand sex from U in return of all she did for U pple. Get elderly advise and act wisely. Best of Luck.