Boyfriend has ex girlfriend on Facebook

So my boyfriend and I have been dating over a year and about six months ago, I found out he still has his ex girlfriend on his Facebook. Honestly, it doesn't really bother me. One reason is they had a baby together about 5 years ago but the baby sadly past away 3 days after he was born. He still goes to his grave every year and keeps stuff for the holidays on the grave site. He told me the reason he still has the girl on his Facebook is because they had a child together. They don't interact or anything so I don't see the point of keeping her on Facebook. But, another reason it doesn't really bother me is because I know he loves me more than anything and would never do anything to hurt me. I guess what I'm wondering is what everyone thinks about it? Should he still have her on Facebook? Am I looking too much into this?