Takes 4ever to finish

I’ve been sleeping with my FWB for a few years now, and honestly, the sex is pretty hit or miss. Sometimes it’s decent, but other times it’s just not enjoyable. Is it a bad thing if a man takes a long time to finish? Could it be me? Often, I end up asking him to stop midway because I get bored or lose interest.

We don’t do any foreplay—he just dives straight in, no kissing or anything, which doesn’t help. To make things more complicated, our friendship is a bit messy. One minute we talk about taking things further, but then I change my mind because, deep down, I don’t think he’s the right person for me. Any advice ?