Ok, I'll try to be as brief as possible -
Relationship ended in 2005, when DC's were 6 and 2.5. From the moment of moving out he didn't pay a penny for the DC's or the house. In fact, I lent him the first months rent & deposit for his flat, which has still not been repaid. In short, DH (with whom I have 2 dc's) and I need to move - for several valid reasons. I have ME, the 3 bed maisonette is not suitable for 6 of us, & DH has a 5 hr commute. After exploring the local area, & the counties either side, we looked at DH's home town, and it ticks ALL the boxes, save proximity to XP & my parents. So in September, a month before we put the flat on the market, we wrote to XP to tell him the situation and suggest ways in which his contact could change (without technically being reduced). Currently he has them Weds & Thurs nights 3.20-8 and every other weekend. Keeping up this level of contact with a 120 mile move would be hard, but do-able. We suggested keeping the alternate weekends, but moving the midweek dinners to become extra holidays on top of his half.
Without sitting down sensibly to talk about it, he (as we expected because he's a twat) has gone to a solicitor and has threatened to go for PR and a Residency Order to swap the arrangements around because I have ME, and because he says moving will unsettle the children and disrupt their relationships with him and his family. He says that the children are showing signs of strain from having extra responsibilties (we think they have a normal amount of age-appropriate chores, and employ someone for six hours a week so they don't have to do anything above that) & we think he's worried that he's not going to see the children, which obviously isn't true.
DH and I think that there's not much chance of him succeeding, as a) we're not denying him contact, or even reducing it, just changing it. b) he lives with his parents, has to walk for 3 minutes to get to his work & has never bothered to learn to drive. c) He's done less school runs that I can count on one hand, only started paying maintenance last year when we went to the CSA, and has never contributed to child care costs & insisted that we do his school runs for five years, threw a hissy fit when we said that would have to change, has done very little homework with them, even when they were seeing him 50/50 in the early years e) has a long standing record of being a daily heavy cannabis smoker, alcohol abuse & self harming after the split, which happened because he was shagging someone from work and because he was a twat who wouldn't grow up and oh, he also owes us about £50,000 in unpaid maintenance, petrol costs, childcare costs, and mortgage extension loans etc.
But I'm still shitting myself that he could take DD and DS1 away from us.
Any ideas.