My brother-in-law is on a dating site and refuses to tell my sister – he gives me the creeps

DEAR DEIDRE: MY brother-in-law has put his profile on a dating site. I don’t know what to do.

He’s been with my sister for 19 years and they have two sons.

I’m 41 and I split with my boyfriend a year ago. Recently, I felt ready to date again so put myself on a dating app.

I started to scroll through the guys but then a photo stopped me in my tracks — it was my brother-in-law.

I did screenshots on my phone and when I next went into the shop he runs, I asked if I could have a word.

I confronted him and asked him whether my sister knew what he was up to.

He went white as a sheet and said: “No. She must not know. But I have very good reasons to do what I’m doing.”

I’m not sure my sister would agree and I know she’d hit the roof if she found out.

Now I don’t want to be near him and keep avoiding her invitations for Sunday lunch. He gives me the creeps. My sister is 46 and my brother-in-law is 49. Their sons are 18 and 15.

They do lots of things together and have a big social life.

Why would he want to cheat?

I’m tempted to tell my sister but it’s a difficult situation for me. She can have bouts of depression and I don’t want to make things worse for her.

But surely she deserves to know what a rat he really is?

DEIDRE SAYS: Yes, she probably does and may well already know.

There will be things going on in their relationship that you don’t know about.

But if you do tell her about him cheating, this will bring her a lot of upset and she may shoot the messenger.

If she doesn’t know what’s going on, she could feel embarrassed, ashamed even, that her sister drew attention to something that she should have realised.

If she suspects that her husband is cheating, she may be dealing with it privately. You confronting her will take away her coping strategy.

Try talking to your brother-in-law again and tell him he’d be better to get some couples’ counselling than risk his marriage – it may be enough to make him think.

My Counselling support pack explains how therapeutic this can be. Give him a copy.

Finding a counsellor yourself will give you a safe forum to offload.