My ex "B" and I were together for 7.5 years, since we were 17 and 19, a few months before going to university together. We broke up in May last year after a long drawn out process of me giving a man too many chances when he had already let me down so many times, he didn't deserve them. He's a good natured, down to earth person who's avoided sorting out his issues for far too long. I love him, but I haven't been in love with him for a while. I've worked very hard in therapy to process the complex feelings that came out of our relationship ending. It was heartbreaking.
We still live together, and we shouldn't be — but believe me, the decision was made in some very difficult circumstances where there really was no other option. We've separated our lives as much as you humanly can while still being under the same roof, and in daily life we function as roommates. There is a contingency in place that if living together becomes too difficult, he will move back in with his mother and continue paying rent here (he suggested this in the first place). You can't "break a lease" here, you're locked in for a year.
This will probably end up happening in the next couple of months, off the advice of my therapist and how it's affecting me moving on. I'm not hung up on him (obviously, new relationship would never have happened if I was), but it's affecting my personal growth.
A month and a half ago, I realised I had a little crush on an online friend "P" who I'd known well for 6 months. Since there is a lot of distance, I wasn't even expecting her to say what she did — that she both liked me too, and was willing to try dating. I say this to be clear that I wasn't looking for anything at all – it just happened. It's only been just over a month as I said, but I like her so, so much. We're compatible in a lot of ways and she's so much fun to spend time with.
I haven't told B yet. I don't want to be dishonest, but the awkwardness and bad feeling it would cause in such a small house when we've been functioning reasonably well so far has been enough for me to hold off. He wouldn't get angry, but he would be very, very upset. I have a problem with sparing his feelings and putting mine second, apparently. That, and it's a very new relationship anyway, and I didn't want to upend everything on something that might not even last/go anywhere.
I know he needs to know at some point. And I was going to wait until he had moved out, but it's getting more difficult as time goes on, especially with some of our mutual friends now knowing (they're very supportive and trust that I'll tell him when I'm ready). Do I wait, or do I just tell him now I can actually see this relationship continuing?
TL;DR: Ex of 7.5 years and I broke up in May. We are locked into a 1 year tenancy/lease since June, having no real choice but to move in together at the time. I have a new LDR girlfriend of just over a month who I have a really good feeling about. When do I tell him?
EDIT: I should make it clear I have no concerns about my safety, and he's never been abusive in any way. I just don't want to hurt him and our good relationship in the house. He's still my very good friend.