Is he cheating? Am I seeing too much into things?

How can you tell if your boyfriend is cheating or if things are just not going well in the relationship? I've had a history of men who cheat- so I automatically think that. We've been together for a few years and have a daughter together. Last week I went out of town with our girls for the week with my sister and her kids for a 'vacation'. Before we left he mentioned he might go bowling with a guy from work one of the nights. Then one day when I called towards the end of the vacation he mentioned he had gone out- to a bar I used to go to frequently, before we got together and said he just went himself and had a few beers- sat at the bar and bullshitted with some guys sitting there, the bartender and some waitresses. Ok. No big deal. So when i get home he has a matchbook lying out from the bar... but then in his coat pocket there was a matchbook from a bowling alley. We've never gone to this bowling alley together- so it's not like I know that it's somewhere he would (cont..)