In 7.13 (Tailgate) there is a tombstone that reads "MOTHER".
Also, in 6.20 (The Exploding Meatball Sub), there is a flashforward where Barney pretends to be ill. It's clear that Cobie was instructed to hide her left ring finger but it is seen that she has no ring. I believe we discussed this lack of ring in 6.20 and in a flashforward in 8.16 Bad Crazy but unless Robin is in on the joke in 6.20 which she doesn't seem to be then it is consistent with what unfortunately did happen which is the B/R divorce.
There are other hints discussed like in 8.20 and 9.19.
P.S I haven't been on here in a long time and only watch episodes occasionally but I miss the community here and what the series was like before the finale.