Since it's your ex it might seem hard.. but he is not your daughter's ex.. and it's obvious she loves him.. Love her enough to not let your relationship with him even enter into this project.. and if you can manage, be gracious about him and wish him well.. Being selfless like that can only help your relationship with your daughter and the positive feelings you have about yourself. Do this project and it probably will not be the last quilt you'll get to make with your daughter.. make it fun and a happy time. It will be well worth the time spent.