That’s a tricky one and you’re certainly not going to make everyone happy whatever decision you make SO… what do you want? What would make you happy? Is he worth risking falling out with your half sister? Have you talked to her about it? Ultimately you have to make the decision here but be very clear about what it is YOU want, the rest will take care of itself.

Probably nothing in truth. If you’ve tried speaking to her and it hasn’t made a difference, there is not a lot more that you can do. It might be wise to back off and give them a bit of space so that they can develop their relationship before you try again and maybe next time, if she’s feeling more confident in her relationship with him, she’ll listen?