Threesomes 👀⁉️

So my boyfriend has brought up having a threesome a couple times and i say im okay with it but deep down a part of me is okay but the other part is kinda not okay.. like every girl never wants to share their boyfriend of course not sexually either.. the thing is im fine with being with another female (sexually) but my jealousy takes over every time i think about another female doing what im suppose to be doing to my man 🙄.. i would look at it as a competition ahaha' like you can do that well i need to one up you by doing something better so it might be interesting.. i just need advice from someone who has had a threesome with their other..