File photo: They've celebrated, commiserated and just hung out with him. Picture: Pixabay

Question: My new partner's best friend is a woman and, while I do trust him, I can't help feeling uncomfortable. 

They have known each other for years and regularly meet for dinner à deux. We are in our late 50s and still work, so barely have enough opportunities to see each other as it is.

I understand that this friendship is important to him, but it hurts that he would prioritise it over our own relationship, especially when we've only been together for a year and free time is so hard to come by. It is bringing out a horribly jealous side to me: am I being unreasonable?

Answer: The short answer? No, you're not. But you need to examine why this situation has arisen, why you feel uncomfortable about it, and how to deal with it.

Meeting your new partner's friends is always an important part of establishing your relationship. These are the people who share more than memories and a sense of humour with your man.

They've celebrated, commiserated and just hung out with him. They've seen him in all his moods, they've listened to his worries and supported his ambitions. They've also heard all about him getting together with you. Their natural reaction ought to be to befriend you.

It's an unusual person who only wants to see their friends one-to-one and a selfish one who doesn't want to include new partners — if only out of curiosity. Friendships have to adjust to everyone's circumstances and this one's no exception.

While I don't think your man is entirely blameless — he has obviously been persuaded that nothing needs to change and hasn't challenged the idea — the fault lies more with his friend.

Whether or not she holds a candle for him, she must know if he's with her, then he can't be spending time with you. I expect you held your tongue initially, not wanting to seem possessive or small-minded, but you could reasonably expect a table for three after a while.

Whatever her circumstances — she might be single or have a remarkably tolerant partner — she seems determined to keep this relationship intimate.

That's not to say neither of you are allowed to see members of the opposite sex alone, or that he can never spend time with her, but it's got to feel mutually comfortable.

Until you've been included, their time together will feel secret and separate, but it's more likely to be a habit he has to break than anything illicit.

Have you met her? Invite yourself along to the next gathering, whether it's for two or 20. Tell her, lightheartedly, that your time with him is precious and you're both having to re-jig your diaries to see each other as often as you'd like.

Tell her it's lovely he has such loyal friends but make your feelings clear. She'll get the hint. If she's truly his best friend, she'll stand aside as you establish your relationship — and be delighted to do so.