If the pay and benefits from your new job offer will be enough for you to live on, then you should take the job.
If your boyfriend really wants to be with you, he'll find a way to leave his mother's home and join you; that does NOT you'll let him live off of you! He has to have his own job and his own place to live! If he can't make that change, no problem... you'll have moved on with your life!
This is a new opportunity to make a life for yourself which isn't contingent upon toxic relationships and a boyfriend that takes you for granted.
Moving to a new place, a new job, etc. won't be easy. Maybe you'll feel lost for awhile. But hold on to your dreams and make it work.
You can do this for yourself.
Good luck, and best wishes!