Marry the right person...of course that's the real trick. Very helpful if the SO has a lucrative & portable career (doctor, nurse, software, accounting, etc).
Avoid other crew members...it's all globe-hopping fun on your days off until you have kids. After that it's probably 90% divorce rate unless somebody quits flying.
Have a career plan and stick to it. The SO needs to be 100% on board with that, or you need to get a new career...or a new SO. If the career plan doesn't pan out, have an exit strategy before you're in too deep. Best to assume that a "regional career" is not a valid option...maybe you'll get lucky, but remember if you're having a good regional career then management is working like hell to replace you. They have all day to figure out how and nothing better to do.