Re: Going to an ex’s wedding
As already suggested, evil MIL always does the trick. 
Some other tips:
- You still have feelings for the ex and have kept all e-mail/texts/letters/gifts from her/her and secretly look at them regularly.
- The ex contacted you when he/she got engaged and confessed his/her undying love for you despite the engagement
- If this is a woman, then the husband is unromantic and doesn’t make enough $ to buy brand new furtunire for the entire house
- If this is a guy, then his wife is fat/can’t cook/doesn’t worship his mother
- During an intimate moment with your spouse…you accidently called out your ex’s name