I think it would be totally okay.
There have been times (more than once) where a friend liked my ex, I actually encouraged her to go for it because I knew they would be a lot better together than he and I were. So I was happy to see them together
.
I guess with some people it depends on how serious it was too. Like where friends won't even consider a guy because their friend likes them and sometimes that gets way too confusing.
Anyways! I would say it's okay