I’m always being jealous of my boyfriend’s family. I used to date a guy for almost 2 years. There were a few problems between us but for the most part I couldn’t help but thinking about his family (sister, parents). I know it is weird and not good. I admit that but I can’t help my feelings. At the moment, I’m seeing a guy (we’re not dating yet). He is a few years older and has a sister with two kids. So most of the time he has to babysit them and I feel utterly jealous even though I’ve never met them. I’m not sure what this jealousy is about but it is a very uncomfortable feeling. Please anyone if you have the same problem, give me some good advice.

I understand your frustration though, a little bit. I was with a guy for two years who had an older sister, one who didn't approve of me. He was a biologist and during the summer months he worked in the field (way way out in the bush) for two weeks, then he'd have four days off. We would make plans for his days off and I would look forward to it. But his sister would call within an hour of him getting home and beg him to come see her because she was bored. He always went out of duty to her, of course. It bothered me and made me feel unimportant (not so much jealous though) because it happened every time he had a weekend off.
When you make someone your number one priority and they don't make you their number one too, it sucks.