I was wondering what some good exercises are to increase my straddle flexibility? I have been doing seated straddles, really trying to get on my sit bones, for a while now...but am still not progressing past 90 degrees. The past week or so I have also been adding this stretch:

Even doing the Straddle - PB Bent... my arms often touch my legs...not so much resting on them, but simply because I don't have the flexibility to not have that happen.
Is there anything else I can be doing?