#1 -- Sponsors according to the AA Big Book are not suppose to be involved with the Sponsees marital matters -- they are not qualified marriage counselors.
#2 -- To be secretive and on the phone so often and spending that much time with ones Sponsor -- would be unhealthy according to the Big Book for it says to not neglect our families.
#3 -- Sounds like hanky Panky going on.
#4 -- Protect yourself -- don't be the one to leave the family home -- tell her that if she wants to leave -- feel free.
#5 -- Don't jump out and get one but, have a good lawyer ready.
M-Bob