My boyfriend pays quite a bit in child support.
His ex-wife with his 2 kids and her new child and new husband recently re-located to the LA area from Texas.
The ex-wife doesn't work and yet her new husband claims my boyfriend's kids on his taxes. It doesn't seem fair that another man is claiming these children on taxes.
My boyfriend pays a substantial amount, always pays for extras like summer camp, new clothes, haircuts, contacts... things like that.
The kids do live with her a majority of the time except the every other weekend/holidays typical schedule.
Child support is determined by her not working and he is working and the new husband is claiming his step children.
Is my boyfriend getting screwed and should pursue this is court or is this just the way it is and we should get over it?

I think it is --just the way it works and you have to get over it.

The custodial parent usually is given the tax exemptions and can assign them to whomever they want (according to the laws of the IRS). What they are doing is perfectly legal and not at all uncommon.