I'm a Realtor. A lot of my peers are either getting out of the business or taking on 2nd jobs.
I've been fortunate and done well, but I've seriously been considering getting a 2nd job to help out. Especially after the wife and I just found out were expecting again.
My problem is pride. I can't figure out what part time job I could get. A few agents wait tables. There is good money in that, but I refuse to. That was a job I held at 17. No way I'm going to go back to it 14 years later when I have a bachelors.
My part time job would also have to not interfere with my real estate career - which also makes it difficult. I mostly meet with buyers and sellers weekday evenings/weekends. But days are spent at inspections, closings, various other appointments, as well as marketing etc.
I've concluded that I need to find either a grave-yard shift job, or an early morning job where I could clock out by 11-12 at the latest.
Rambling here, but yeah to answer the OP's questions, I've given thought to getting a 2nd job.