Is this my OCD, please help...what to do?

So 4 weeks ago my ex dumped me. We were in a very long relationship and I took it unbelievably hard. I'm still definitely not whole and have feelings for her but am trying to get over them.

I also have OCD and have had a few various themes. Is this one of them and what should I do to get over this?

So I have two roommates who are both my good friends. One of them is still currently friends with my ex and text's her from time to time, and they even went to a concert a few days ago (not just together, in a group of several people).

The other wasn't great friends with my ex and was more friends with me.

When I had closure with my ex about three days ago she said that there was never anyone else and I didn't even ask but she also said she hadn't hooked up with anyone else yet. She also said she wouldn't pursue my roommates.

I'm getting distressing thoughts about what if they are hooking up with her. I know they are irrational and I want to get over them; especially because I'm not with my ex anymore and what she does shouldn't be my business. It's just a piece of me would be devastated if they were. And yet there the thoughts are.I feel the compulsion to ask them this and have even wanted to look at their phones (I'm not going to do this).

The reason why I thought this are because: One of the friends is still in contact with her and also recently became single.

I have the thoughts about the other one because the night when we broke up I texted him (who wasn't good friends with my ex), and he already knew because she texted him about it. The rational part of me is pretty certain that she texted him to let him know that I took it very badly and needed some support. The OCD side of me...well you know what that thought...

They are decent guys and I would rationally be shocked if they would do this because they know that I'm not over her and it's sort of unwritten bro code.

Please help! I know I should just let the thoughts come and deal with the anxiety but I'm having a tough time with this and really want to know but don't want to ask them.

This sucks