Ay mommy, ito talaga ang mahirap na desisyon, a few of us mum friends went through the same dilemma, at honestly, mas okay kung may marriage certificate na before mag-ligation kasi it's such a permanent thing, lalo na if your relationship status might change down the line. Since 5 years na kayo together, maybe kausapin mo talaga ng malinaw with your partner kung seryoso ba talaga sya sa inyo, at kung kasal na talaga ang plan, kasi ito ay joint decision talaga at dapat both of you sure. The medical side naman, best to discuss with your OB lahat ng options and risks, lalo na after multiple CS, para sure ka sa ginagawa mo. Wishing you all the best, mommy, this is a big one, kaya take your time deciding.