Just a heads up that if your ex misses his days with the kids, it is best to keep notes on all that. After a certain amount of time, you can make a case for more custody which would require him to pay more. I know legal fees can be costly, but with twins who are 5, it may be worth it to go for more custody. A lawyer could tell you how many days he needs to be missing for you to have a case.
Wishing you continued happiness.
Me 41, H 47, M 15 yrs, S11, S13 BD 1: 11/4/14 we work on it; really I pretzel myself BD 2: 3/31/15 H goes down to "dorm room" 8/15: H back to MBR 10/15: H back in dorm room 1/18: H files, now divorced