Who can claim my step son

My husband and my husbands ex all live in Oregon. My question is, who can claim my step son? Last year my husbands ex didn't work. Their son lived with her but he was mostly at our house. We've documented everything. At the end of the year my husband claimed his son. His ex filed a amendment because she wanted her boyfriend, whom she and my husbands son lived with, to claim him. Could he have? My second question is we are going into mediation in a couple of weeks. We are going to offer my husbands ex shared custody. Which of them can claim the boy? She worked for 4 months at the beginning of the year but she's the type of mom that she has child support coming in one place and a boyfriend in the other corner so she refuses to work. Can my husband claim him or if she does work do they both claim him?

[MySonsMom]

2 people cannot claim him..normally what is fair is that they switch from year to year..one year your husband can claim him the next year the ex does..that is what normally happens that makes it fair for both parents. If 2 people claim him on the same year can cause some problems with the irs..and you don't want to get into problems with them..good luck

I know that for my stepson, my husband claims him one year and the ex gets him the next. However, old friends of ours had it where the father (non-custodial parent) gotto claim the son every year since he was paying child support. I think that it just depends on what is agreed to or ordered in the court judgment.