Now that they’re back together I’m questioning whether to say something to her about it. Obviously people can change, but I just feel in my heart she can do better.
As a plot twist, she also just found out she’s pregnant with this new guy’s baby, and she’s now in tremendous turmoil about what to do.
It seems cruel to unload one more thing onto her already full plate, especially if she decides to keep the baby and pursue a relationship. I’m feeling lost at how best to support my friend and would love an outsider’s perspective on a super-complicated situation.
Best Friend: Super-complicated for her — for you, I’m not so sure.
Your only decision is whether to tell. And if you don’t want to, then you have cover: The information you possess, and that she doesn’t, is arguably no longer useful. She knows he was unfaithful to her in their first go-round; isn’t that enough about his past for her to work from?
You also have justification to tell: Cheating on a partner and hitting on her best friend are similar awfulnesses, but they’re not the same.
There’s also the matter of how you behave around them. If you can’t relax and it’s hurting your friendship with her, then a best friend deserves to know at least the general outlines of why.
If you settle on transparency, then don’t dance around. Just tell her. “I would have told you then, but you broke up and I thought it was moot. I also know he may have changed since then. I’m telling you now only so you understand my awkwardness. I will back you regardless, whatever you choose.”
Meanwhile, she needs to assess his present-day character while in the turmoil of a divorce, a pregnancy and (no doubt) a riptide of second-guessing. You can help her think just by listening to her carefully and, as opportunities arise and if she’s receptive, asking her some emotional essay questions:
“Looking back on your biggest regrets, would you say they’re from being rash, or too cautious? Pessimism, or wishful thinking? Give examples.”
“Is there something you’re afraid to say out loud, or even admit to yourself?”
“If you could make any outcome happen, which would you choose?” Then, “Okay, how much of that is yours to decide? What’s standing in the way?”
“Are there any wrong decisions here, or are they just different?”
By all means, substitute these prompts with your own; the point is to offer her, through all the swirling emotions, a place to plant her feet.
And to know she still might not use it. (Or appreciate it.)
This has no bearing on how you support your friend through her immediate crisis, but something else to keep in mind: Years ago you kept information from her about her then-flame. I’m not saying that was wrong; I don’t know all the facts and trust you had your reasons. However, it’s worth mentally returning to that choice now, long enough to update how you’d handle it if something similar were to happen again. The simplest way to be a good friend is still just caring enough to try to get it right.