There are people who've managed to keep the same partner throughout their careers in airlines, but they are few and far between. I'd venture to say that the majority of those are survivors from an earlier, less pressured, era.
I know of almost no-one who's joined the industry in the last 5 or 6 years who's managed to keep their marriage going. There's no support for relationships in this industry; when you're away, your partner is on their own. They either learn to survive the single life, doing all the jobs that you once did for the household, or they ship out. They usually ship out, I'm afraid.
This is one of the most fundamental differences between the airlines and the military, where I did 22 years. In the military, there was a support system for spouses left behind. Social occasions included those left on their own; the much-decried wives clubs kept an eye out for all the vulnerable ones and made sure they were looked after. The burdens were shared. That just does not happen in the airlines (nor, I'd guess, in most other careers).
Would I have joined the airlines if I'd known more about what it's really like? No, I probably wouldn't.