Any kind of breach of trust breaks the bond of love. Trust is at the core of Love. If you don't trust the person you're with, then you can't love that person.
I define "love" and "being in love" as very different things. "Being in love" is synonymous with infatuation to me and is something you can fall in and out of rather easily. Real love, on the other hand, is not something you can fall into and doesn't happen by accident. Real Love, like Trust, is a choice (whereas infatuation is not) that can only be made after getting to know someone over a period of time. Real Love is a commitment - to stand by your partner through good times and bad.
**EDIT**
It seems that some have taken issue with my definition, which is fair. The word "Love" is so convoluted in meaning that it's about as easy to define as the word "God". But I stand by my definition. Some seem to think that Trust has nothing to do with Love, but I can't disagree more. The foundation of Love is built on Trust. If you don't trust someone, the most you can be is infatuated with (or attached to) that person, but infatuation is not love.
Every good relationship is built on the foundation of trust, which requires honesty and good communication. Yes, trust is involved in business relationships as well (anything involving people involves relationships of some kind), but to say that trust has nothing to do with love is completely inaccurate.
You can't truly love someone until you can trust that person with your feelings. If you don't trust someone with your feelings, then you don't love that person. You may be attached to that person, you may be infatuated with that person, you may experience a whole wide range of emotions about that person, but real love is built on a foundation of trust. You can't have love without it. Love without Trust = Attachment / Infatuation.
An attachment to someone who has betrayed your trust is not love. But you can choose to forgive someone who has betrayed you so that there's a chance to rebuild that trust again. But in the end, real love is all about each partner trusting each other with their feelings (which requires vulnerability, which in turn requires trust).
When I tell my partner "I love you", what I'm really saying is "I trust you completely".
Furthermore, if there are "trust issues" in a relationship, chances are you aren't involved in a healthy relationship. Any relationship that has "trust issues" is pretty much doomed to either fail, or be dysfunctional.