As the guys have pointed out there are many threads on both subjects you ask about. That said 42 is far from old. The important thing to realize is as a pilot you have a finite amount of time left in your career. Mandatory retirement is 65 so if you started today and got hired at 44 that would give you a 21 yr career (which isn’t bad at all). You would have no problem getting hired at a Regional as there is currently a pilot shortage, the big question for you would probably be what to do with your career? Most pilots aspire to fly for a Major and at 42 you would still probably have the opportunity, the question is would you want to? The airlines are funny in that every change you make often returns you to the bottom since everything is based on seniority. When you’re first hired you’re obviously very junior and that usually means a lousy schedule and often not the base or aircraft you may want. As you gain seniority things will get better but then you’re going to want to upgrade. Well when you upgrade you’ll now be a junior Capt and again that means lousy schedule etc. In your case you’d probably be looking at 4-6yrs to upgrade and build some Capt time to move on to a Major that that puts you at around 50 (give or take). Now at 50 will you want to move to a Major and start over as a new First Officer with a lousy schedule etc. Maybe you would? Maybe you wouldn’t? Bottomline either way you absolutely could have a nice career as an airline pilot you just may find yourself having to make some tough decisions along the way.
The whole airline pilot divorce rate is somewhat of a cliché and not necessarily correct. I know plenty of pilots who’ve been married their whole careers and others who haven’t. I also know plenty of non-pilots who’ve been divorced. I know many pilots who say the only reason they’re still married is their career as a little time apart keeps things “fresh” and less at eachothers throats. In my humble opinion you have no better chance of divorce being a pilot as you would being a plumber. If you have a good healthy marriage you’ll be fine if you don’t you won’t. As for schedules there really is no such thing as a “normal” or “regular” pilot schedule. Depending on the airline, the airplane and your seniority, you could be home every night, fly 8 legs a day and only work 10 days a month to being gone 20 days a month and only actually fly 1 leg every few days. If you work hard and do your homework you can eventually find the type of operation that fits your lifestyle.