Traveling to Spain for residency without return ticket

I am and American citizen whose husband is from Denmark and is currently a permanent resident of Spain. My son (who is dual citizen of USA and Denmark) and I will be flying to Spain to join my husband in 3 weeks, and plan on staying for longer than 3 months. I plan on becoming a resident as soon as I arrive back in Spain...I have all of the paperwork necessary to do so. My issue is that I will be arriving in Spain without a return ticket to the US. Will this be an issue since I don't currently have my Spanish residency? Do I still need a return ticket?

You shouldn't encounter any problems, but soon as you land in Spain make sure that you request your permit straight away. If after your three month valid stay period you have still not received your permit ( you should have done so) but if you haven't, make sure you carry with you a copy of your marriage certificate as well as your passport.