My FWB just contacted me after his breakup to roleplay as his ex girlfriend

I met a guy at my friend’s birthday party who I found pretty interesting and attractive. We were super wasted after the party and ended up having sex while he was driving me home. We kept contact with each other after that night because it was a really fun night for both of us and we decided to become fwbs, mainly because I wasn’t ready to commit to a relationship. We had a bit of fun for a while but after he got a girlfriend, we mutually agreed to cut off contacts with each other and I respected his decision to care for his girlfriend so I stayed away from him and go on with my own life.

Today he contacted me again and told me that he broke up with his girlfriend and how he is feeling really down and couldn’t move on. He asked me for a favour if I’d be open to dress and style like her and role play as his now ex girlfriend so he could have sex with ‘her’ one last time. I told him I’ll think about it because I don’t know how I should feel about this. I’m very open to try new ideas in sex but slightly disappointed because he’ll be thinking of another girl while having sex with me. I guess it’s normal for role play, I’m not against it, but just confused about the situation. I’ve never role played before.