I believe most of us, if not all of us, desire to be in a trusting and honest relationship. The circumstances you have experienced are consistent with far less honesty, trust, integrity, which speaks to once lack of character these are often deeply and grained aspects that ones personality. It’s not to say that a person cannot change, because they can if they put forth the relentless effort. Sadly, many individuals continue down the road of manipulation, lack of truthfulness, in general dishonesty. True commitment from such individuals is often hard to come by. These are not necessarily bad people. They simply have difficulty being truthful and honest in relationships. A happy long-term life is often determined by the quality of the decisions we make. Most of us know when we are making a less than good decision.